einfach-produktiv — Frontend

Next.js frontend for einfach-produktiv.mk360.de, Coolify-managed and deployed from this repo (git.mk360.de/Marco/einfach-produktiv). For the VPS-wide infrastructure this app runs on (Caddy, Coolify, Gitea, the shared Payload instance), see ~/dev/README.md — this file only covers what's specific to this project.

Stack

• Next.js 16.2.9 (App Router, output: "standalone" for a small Docker image — see AGENTS.md before touching anything version-specific, this Next.js release differs from older training-data conventions)
• React 19.2.4, Tailwind CSS 4, Motion for animation
• @react-pdf/renderer for invoice PDF generation (see "Invoice PDFs" below) — no headless-browser dependency
• No local database — all editable content (and now orders/customer accounts) lives in the shared Payload CMS at payload.mk360.de (see below). Customer auth is Payload's own (a second, separate auth: true collection there, customers — not this app's own user store), bridged via an httpOnly session cookie this app mints itself; see "Orders & customer accounts" below.

Getting started

npm install
npm run dev

Open http://localhost:3000. npm run build && npm run start reproduces the production build locally — do this before pushing, since Coolify builds with --no-cache and a failed build only surfaces there otherwise.

Environment variables: PAYLOAD_URL (defaults to https://payload.mk360.de if unset, see app/lib/payload.ts). PAYLOAD_PREVIEW_SECRET (no safe default — required for Live Preview, see below; must match the value set on the Payload backend). NEXT_PUBLIC_PAYLOAD_URL (optional, defaults to the same https://payload.mk360.de — only needed if the client-side Live Preview components should ever point somewhere else). DISCOUNT_SERVICE_SECRET (no safe default — required for discount codes to validate/redeem at all; must match the value set on the Payload backend). ORDER_SERVICE_SECRET (no safe default — required for /api/checkout to persist an order in Payload at all, for /api/account/verify-email to look up a customer by their verification token, and for getCompanySettings() to read the company-settings collection (seller data for invoice PDFs); must match the value set on the Payload backend — also used there for the same header). SMTP_USER/SMTP_PASSWORD (no safe default — required for app/lib/alertAdmin.ts's critical-failure alerts and resend-verification emails; does not need to match anything on the Payload side — this app's SMTP connection is deliberately independent, see the "Monitoring & alerting" section). Set in Coolify's app settings for production, not in a committed .env.

Pages

Route	Purpose
/	Home — hero, product spotlight, tools grid, trust row
/shop	Product grid (all active products for this tenant)
/blog, /blog/[slug]	Blog overview + post detail
/cart	Cart (localStorage-backed, see below)
/checkout	Shipping + payment method selection, order summary
/bestellbestaetigung	Order confirmation — reads the one-time snapshot /checkout wrote
/konto/login	Customer login
/konto/bestellungen, /konto/bestellungen/[orderNumber]	Order history + order detail (own orders only)
/konto/profil	Profile/address editing + password change
/challenge	"Mini-Challenge" tool
/todo-cards	"Todo-Karten" tool
/newsletter	Newsletter signup
/versand	Shipping policy (timeframes, costs)
/impressum, /datenschutz, /agb, /widerruf	Legal pages (from Payload, see legal-pages below)

Content backend: Payload CMS

This app is one tenant in a shared, multi-tenant Payload instance also used by other projects on the same VPS (see docker/payload/ in the infra repo). All content queries go through app/lib/payload.ts, which hardcodes TENANT_SLUG = "einfach-produktiv" and filters every request with where[tenant.slug][equals]=einfach-produktiv — the tenant field itself is injected automatically into every collection below by Payload's multiTenantPlugin, not defined in this app.

/api/products is this app's own same-origin proxy route (app/api/products/route.ts) in front of getProducts() — used by client components (cart, related products) that need the catalog reactively, so they don't talk to Payload's API directly and reuse Next.js's fetch cache instead of an extra round trip.

Collections used by this tenant

Most reads are public (access.read: () => true); writes are always admin-gated in the Payload admin UI at payload.mk360.de/admin. A growing subset below is not public-read at all (discount-codes, orders, customers, number-ranges, company-settings) — each row says so and explains what does have access instead.

Collection (slug)	Used for	Key fields
products	/shop grid, homepage spotlight, cart, checkout	name, slug (cart item id — not Payload's numeric id, so existing localStorage carts survive catalog changes), description, price, compareAtPrice (optional strikethrough), image, detailHref, sortOrder, active (hides a product from the shop grid/spotlight/related-products only — cart/checkout/its own detail page still resolve it regardless, see Discount codes section below for the same opt-in-filtering principle), spotlight + spotlightEyebrow/spotlightHeadline/spotlightText/spotlightImage (homepage "Neu im Shop" section — falls back to image if no dedicated spotlight image is set; forced onto the sole active product when exactly 1 exists, see getSpotlightProduct()), taxRatePercent (optional per-product VAT override, see "Product bundles & per-product tax rates" below), bundleItems (optional — makes this product a bundle)
discount-codes	Cart discount input (/cart, display-only on /checkout)	code, type (percent/fixed), value, validFrom/validUntil, minOrderValue, maxRedemptions, redemptionCount (server-incremented only), active. Not public-read — see Discount codes section below
posts	/blog, /blog/[slug]	title, slug, category (relation to categories), excerpt, thumbnail, content (richText), readTime (auto-calculated on save from word count), featured (shown as the /blog hero post; most-recently-published wins if several are marked), publishedAt, quoteLabel (label + icon + underline shown next to every blockquote in content, default "Merke dir:" — leave empty to hide that framing, the blockquote text itself still renders), relatedProduct (optional relation to products, powers the "Passend dazu" card at the end of the post — leave empty to hide that card, or empty if the linked product has no detailHref)
categories	Blog post categorization	name, slug (unique per tenant, not globally)
legal-pages	/impressum, /datenschutz, /agb, /widerruf	type (impressum/datenschutz/agb/widerruf, one doc per type per tenant), title, content (richText), attachment (optional file, e.g. the Muster-Widerrufsformular PDF)
trust-badges	Horizontal "Schneller Versand / Versandkostenfrei / Mit Liebe verpackt" row — shown on /shop, /cart, /checkout, /widerruf, /agb, 404	title, description (supports {{lieferzeit}}/{{kostenfreiab}} placeholders, resolved by the frontend from shipping-settings/shipping-methods at render time — not by Payload itself), icon, sortOrder
cart-trust-badges	Sidebar bullets on /cart (title only) and /checkout (title + description) — deliberately a separate collection from trust-badges so the two pages can't drift into showing different claims	title, description, icon, sortOrder
shipping-methods	/checkout shipping selection	title (no day-range in the title text — that lives in shipping-settings now, keeping both in one title used to drift), description, price, freeShippingThreshold (per-method, optional — leave empty for a method that should never be free, e.g. Express), active (inactive methods are hidden, not shown disabled), sortOrder
shipping-settings	Delivery-time disclosure shown on /shop, homepage spotlight, ToDo-Karten, /cart, /checkout, /versand (Art. 246a §1 Abs.1 Nr.8 EGBGB requires this visible before checkout)	handlingDaysMin/handlingDaysMax (processing time before it ships), transitDaysMin/transitDaysMax (carrier time) — the app derives the combined total itself. One row per tenant.
payment-methods	/checkout payment selection	title, icons (array — e.g. 3 logos for "Kreditkarte"), active, sortOrder
werkzeuge-cards	Homepage "Meine Werkzeuge" 3-card grid	title, description, icon, ctaLabel, ctaHref, sortOrder
testimonials	Customer testimonial grids on /todo-cards, /newsletter, /challenge	quote, name, role, avatar, page (todo-cards/newsletter/challenge — which page's grid this appears in), sortOrder. The single-quote "photo band" testimonials on /not-found and /bestellbestaetigung are a different shape (no avatar/role) and stay hardcoded, not part of this collection.
media	Shared upload collection backing every image/icon/thumbnail/attachment field above	alt (required for images), title (optional display name for download links)
orders	Persisted checkout orders, /konto/bestellungen*	orderNumber, invoiceNumber/invoiceIssuedAt, correctionInvoiceNumber/correctionInvoiceIssuedAt (see "Invoice PDFs" below), status (received/processing/shipped/delivered/cancelled/return_requested/returned — the first 4 maintained by hand in the admin, no carrier API; the rest see "Order cancellation & returns"), returnReason (captured from the customer on a return request), full address/items (each with a snapshotted taxRatePercent/bundleContents)/totals at order time. Not public-read — created only via ORDER_SERVICE_SECRET, read/updated by admin or the order's own customer
customers	Storefront accounts — register/login/order-history, a second auth: true collection separate from the Payload admin's own users login	customerNumber, firstName/lastName/email, one default address, cart (server-side mirror), emailVerified (non-blocking). Not public-read — see "Orders & customer accounts" below
number-ranges	Admin-configurable prefix + running counter for customer/order/invoice/correction-invoice numbers — one row per tenant	customerPrefix/customerNext/customerPadding, orderPrefix/orderNext/orderPadding, invoicePrefix/invoiceNext/invoicePadding, correctionInvoicePrefix/correctionInvoiceNext/correctionInvoicePadding (Stornorechnung/Gutschrift — its own gapless sequence, not the same counter as invoice*, see "Invoice PDFs" below). Admin-only, no frontend read at all — internal to the two beforeChange hooks that assign these numbers
email-templates	Editable subject/heading/body/footer for all 6 transactional emails this shop sends (see "Email templates & Live Preview" and "Status-change emails" below)	type (order-confirmation/password-reset/order-shipped/order-cancelled/order-return-requested/order-returned), subject, heading, bodyText, footerText. Public-read, has a Live Preview button
company-settings	Structured business data for invoice PDFs and every email's legal footer (Anbieterkennzeichnung, see "Invoice PDFs" below) — one row per tenant, own Company admin group (not Commerce — this is business identity, not a storefront concern)	sellerName/sellerStreet/sellerZip/sellerCity/sellerCountry/sellerEmail, vatId, taxRatePercent (admin-editable, not hardcoded), bankName/iban/bic (iban/bic format-validated + uppercase-normalized; bankName stays free text — replaced a single free-text bankDetails field). Not public-read — admin or ORDER_SERVICE_SECRET. Has a Live Preview button — see "Company Settings & Live Preview" below

All of the above except company-settings, media, users, tenants are grouped in the Payload admin sidebar under Commerce (products, discount-codes, orders, customers, number-ranges, email-templates, shipping-methods, shipping-settings, payment-methods, trust-badges, cart-trust-badges) or Content (posts, categories, legal-pages, werkzeuge-cards, testimonials). company-settings sits in its own Company group; media/users/tenants sit under Platform — users and tenants are hidden from non-super-admins' nav entirely, and every tenant-scoped collection's own "assigned tenant" field is hidden from non-super-admins in the edit view (though not yet the list view's column — see the infra README's Payload CMS section for why that one's a harder fix).

What an admin can actually configure without a code deploy, at a glance: product/shipping/payment catalog data and active toggles (incl. per-product tax-rate overrides and defining a product as a bundle), discount codes, all page content (blog/legal/testimonials/trust badges), delivery-time disclosure (shipping-settings), order/customer/invoice numbering schemes (number-ranges), all 6 email wordings (email-templates, with Live Preview), and invoice seller data, bank details, and VAT rate (company-settings — also what every email's legal footer is sourced from). What still requires a code change: adding a new field to any collection (needs a migration), payment processing itself (not built), and anything structural in orders/customers beyond status/returnReason and the profile fields already exposed on /konto/profil.

Adding a new field to any collection above requires editing the collection file in docker/payload/src/collections/ and a migration, which does need a deploy of the Payload service.

Live Preview

posts, legal-pages, and testimonials support Payload's Live Preview — opening a document in the Payload admin shows this app's real rendered page in an iframe, updating as you type, no save required. email-templates also has Live Preview, but against a synthetic page + sample data rather than one of these three's own real page — different enough to cover separately, see "Email templates & Live Preview" further below.

• app/api/preview/route.ts — validates PAYLOAD_PREVIEW_SECRET (matching value required on the Payload side too, or this route 401s) and a path, enables Next.js Draft Mode, then redirects into the real page. This is the link Payload's livePreview.url resolvers point at (see docker/payload/src/lib/previewUrl.ts in the infra repo) — never the page directly.
• Each supported page checks draftMode().isEnabled and renders a "use client" Live-Preview-aware component instead of the plain static one only when it's true — ordinary visitors are never in Draft Mode, so they always get the plain version with zero extra client JS:
  • app/components/LiveRichText.tsx — the 4 legal pages' body content (their headings/sidebars are hardcoded per page, not CMS-sourced, so content is the only field worth live-previewing there)
  • app/blog/[slug]/components/LivePostContent.tsx — title/excerpt/ thumbnail/body of a blog post (the author bio card, "Weiterlesen" card, and Footer stay static — they either aren't post-specific or are about a different post, not the one open in the admin)
  • app/components/LiveTestimonialsGrid.tsx — the one testimonial currently open in the admin, merged by id into the rest of that page's already-fetched grid (Live Preview is inherently single-document, but this page renders several at once)
• All three use @payloadcms/live-preview-react's useLivePreview hook and reuse the same mapping functions (mapPayloadPost, mapPayloadTestimonial, exported from app/lib/payload.ts) the plain server-side fetchers use, so the two code paths can't silently drift apart.
• app/lib/payload.ts deliberately never imports next/headers itself — callers (the Server Component pages) call draftMode() themselves and pass the result in as a plain { draft: boolean } option. Importing next/headers anywhere in that module breaks the production build the moment a "use client" component (which also needs this file's mapping functions/types) tries to bundle it — a real RSC-boundary regression hit once already when adding this feature.

Discount codes

Applied in /cart only (/checkout displays the already-applied result, no second input) — real server-side validation, not just a client-side check against Payload's public API, unlike most content on this site.

• Manual input field on /cart (CartContent.tsx) — a text field + "Anwenden" button, shown whenever no code is currently applied and Payload actually has at least one active code right now (hasActiveDiscountCode() in discountServer.ts, where[active][equals]=true, ISR-cached 60s — no point offering an open field that could never validate against anything). Once applied, the field is replaced by a read-only result + "Entfernen" link, shown regardless of that check (an already-applied code, e.g. from an older session, still needs somewhere to display even if no other code happens to be active right now). ?code=SAVE10 on the /cart URL still auto-applies once on arrival (a useEffect reading useSearchParams() — requires /cart's page.tsx to wrap CartContent in <Suspense>, a Next.js requirement for any useSearchParams() consumer) regardless of hasActiveDiscountCode() too, so a marketing link still works without the shopper typing anything; if that auto-apply fails, the error shows even without the manual field present.
• app/lib/discountServer.ts (server-only, imported exclusively by the two route handlers below — never by a "use client" component, same reasoning as Live Preview's next/headers lesson above) talks to Payload's discount-codes collection using an x-discount-service-secret header (DISCOUNT_SERVICE_SECRET), since that collection isn't public-read.
• app/api/discount/validate/route.ts — read-only check (active / validity window / minimum order value / remaining redemptions), called when a shopper clicks "Anwenden" in the cart.
• app/api/discount/redeem/route.ts — re-validates, then increments the collection's redemptionCount. Called exactly once, from CheckoutContent.tsx's handlePurchase(), right before the OrderSnapshot is written — a code that expired or hit its redemption cap between being applied in the cart and the actual purchase click fails the purchase with an inline error instead of silently completing.
• app/lib/discount.ts mirrors lib/cart.ts's exact localStorage + useSyncExternalStore pattern, so the applied code survives the /cart → /checkout navigation the same way the cart itself does.
• app/lib/cartTotals.ts — computeSubtotal()/computeCartTotals(), factored out of what used to be independently-duplicated subtotal/ savings/total math in CartContent.tsx, CheckoutContent.tsx, and BestellbestaetigungContent.tsx; now also folds in the discount amount (clamped so a total can never go negative). OrderSnapshot persists the applied discountCode/discountAmount so the confirmation page shows what actually happened, not a fresh re-derivation.
• Known, accepted limitation: the redeem route's read-then-increment isn't atomic against a true concurrent race on a capped code's very last redemption — not worth custom atomic SQL at this shop's traffic level.

Cart & checkout

• Cart (app/lib/cart.ts) is entirely client-side, stored in localStorage under ep_cart, keyed by each product's slug. Still the source of truth while browsing — the server-side mirror (see below) only exists to carry a logged-in customer's cart across devices/browsers.
• app/cart/components/RelatedProducts.tsx only ever suggests products not already in the cart — it stopped falling back to re-suggesting an already-in-cart product just to pad the grid out to 3 cards, so with a small catalog it can render fewer cards (down to 1, centered in the 12-column grid) rather than recommending something already added.
• /checkout's "Jetzt kaufen" always goes through POST /api/checkout. That route re-prices the entire cart server-side from Payload's live product data (never trusts client-submitted prices), re-validates+redeems a discount code exactly once, registers a new account inline if nobody's logged in yet ("Konto Pflicht" — see below), and only then creates the order in Payload's orders collection via app/lib/orderServer.ts. subtotal/discountAmount/total are each rounded to 2 decimals (roundMoney()) right before being persisted — plain float arithmetic on a summed/percent-discounted cart drifts into values like 84.30000000000001, invisible wherever a display already ran the number through formatPrice()'s toFixed(2), but stored as-is otherwise and visible raw in the Payload admin's plain number field for total. app/lib/order.ts's OrderSnapshot is still written to sessionStorage for /bestellbestaetigung to read once, but its orderNumber/orderDateIso now come back from that Payload create call, not generated client-side.
• Order confirmation email is sent from /api/checkout/route.ts right after a successful createOrder() — fire-and-forget (app/lib/orderEmail.ts's sendOrderConfirmationEmail()), never blocks or fails the checkout response itself; a send failure alerts admin instead (sendCriticalAlert, lower severity than the "order not persisted" alert, since the order itself is safe either way). Content comes from the published order-confirmation row in Payload's email-templates collection — see "Email templates & Live Preview" below for how that's edited/previewed. As of the invoice PDF feature (see below), this same send also carries the order's invoice PDF as an attachment.
• Still not built: real payment processing — the checkout button is labelled "zahlungspflichtig" but nothing actually captures a payment yet. See project_backend_checkout_plan in the assistant's own memory.

VAT display

Every price shown storefront-wide says "inkl. X% MwSt." with the actual resolved rate (app/lib/cartTotals.ts's effectiveTaxRate(product, defaultRate) — a product's own taxRatePercent override if set, otherwise the tenant default from company-settings), not a generic "inkl. MwSt." disclosure — getDefaultTaxRatePercent() in app/lib/payload.ts is a separate, ISR-cached (60s) fetch of just that one number, deliberately not getCompanySettings() itself (that one is cache: "no-store" for its invoice-generation callers, where always-fresh bank details matter; the display rate only needs the same freshness every other public catalog fetch already has).

A cart/checkout/order-confirmation total additionally shows the actual € amount of VAT included, not just a percentage — computeTaxBreakdown(), imported from @einfach-produktiv/invoicing (a shared package consumed by both this repo and the Payload backend as a git dependency — see "Invoice PDFs" below; it used to be an independently-duplicated groupByTaxRate() inside invoicePdf.tsx/correctionInvoicePdf.tsx, both of which have since moved into that package too) groups line items by their effective rate and reports each group's actual tax amount; app/components/VatBreakdown.tsx renders a single "enthält X% MwSt.: Y €" line when the cart/order has one rate, or one line per rate when it spans more than one. Used on /cart, /checkout, /bestellbestaetigung, the order-confirmation email (emailTemplates.ts's renderOrderConfirmationHtml, which already carried per-item taxRatePercent but didn't render it before), and both account order pages (see "Orders & customer accounts" below) — the account order list additionally shows up to 4 product thumbnails per order row (getProductImagesByIds() in app/lib/payload.ts, a plain product-id → image-url lookup separate from the slug-keyed catalog, since an order only ever snapshots a numeric product id).

Checkout state persistence

app/lib/checkoutDraft.ts — localStorage under ep_checkout_draft, plain read/write functions (not useSyncExternalStore like cart.ts/ discount.ts: CheckoutContent is this draft's only reader, no cross-component subscription to keep in sync). Every address-card field (name, email, delivery method, street/Packstation, PLZ/Ort/Land, the shipping-address-override fields below, newsletter opt-in) plus the selected shipping/payment method is now a controlled input backed by this draft, restored on mount (a useEffect-deferred read, same SSR/hydration- mismatch avoidance as BestellbestaetigungContent's own sessionStorage read) and cleared on a completed purchase. password is deliberately excluded — stays a plain uncontrolled, unpersisted input.

Optional deviating shipping address

"1. Rechnungsadresse" always collects a plain street address now — no Lieferart (Lieferadresse/Packstation) toggle there anymore, since a Packstation isn't a valid billing address for an invoice. A separate checkbox ("Abweichende Lieferadresse verwenden") reveals a second address section with its own delivery-method toggle (own name + delivery method + street/Packstation/PLZ/Ort/Land) — that's the only place Packstation delivery is offered at all. When used, the order's original address fields stay the billing address (used for the invoice's "An" block regardless), and the shipping*-prefixed fields (hasDifferentShippingAddress, shippingFirstName/shippingLastName/shippingDeliveryMethod/ shippingStreet/shippingPackstationNumber/shippingPostNumber/ shippingZip/shippingCity/shippingCountry — mirrored 1:1 on the Payload orders collection, see the Payload README) determine where the order actually ships. /api/checkout/route.ts validates the override the same way it already validated the primary address (required fields, street-xor-Packstation depending on the chosen delivery method). The invoice PDF shows a third "Lieferadresse" address block alongside Von/An when set (see "Invoice PDFs" below); /konto/bestellungen/[orderNumber] shows both addresses too, relabeling the first one "Rechnungsadresse" instead of "Lieferadresse" only once there's an actual second address to distinguish it from.

Product variants

A cart line's identity is (id, variant) together, not id alone — app/lib/cart.ts's CartItem gained an optional variant?: string field (the selected products.variants[].name), and every function that used to match a line by id (addToCart/removeFromCart/setQuantity) now matches by both via a shared sameLine() helper, so two lines for the same product with different variants stay genuinely separate entries instead of merging or clobbering each other. variant undefined on both sides (the common no-variants case) still matches by simple equality — every pre-existing call site that never passes a variant keeps working unchanged.

Where a variant gets picked: both AddToCartInlineButton (/shop, /cart's related-products grid) and AddToCartButton (the marketing-page-specific one on /todo-cards' Hero + Pricing panel and the homepage spotlight) render a <select> above the button when their variants prop is non-empty, defaulting to the first in-stock variant. All five call sites already fetch the full product server-side (getProducts()/getProductBySlug()/getSpotlightProduct()), so product.variants and product.outOfStock are simply passed straight through — no separate data-fetch needed for AddToCartButton's two pages.

Out-of-stock UI: app/lib/payload.ts's isOutOfStock() derives Product.outOfStock (and each variants[].outOfStock) from trackInventory/stock/allowBackorder — true only when inventory is tracked, backorders aren't allowed, and stock <= 0. Both add-to-cart buttons disable themselves and show "Ausverkauft" for whichever variant is currently selected (or the plain product, when there are no variants); ProductGrid.tsx additionally shows an "Ausverkauft" badge (replacing any discount/low-stock badge — a sold-out product has nothing else useful to show) once every variant of a product is out — one sold-out variant among several just reads as such in the picker itself, not as a misleading blanket badge.

Low-stock warning: app/lib/payload.ts's isLowStock() derives Product.lowStock (and each variants[].lowStock) from trackInventory/ stock/lowStockThreshold the same way outOfStock is derived — true only when inventory is tracked, stock is above zero (out-of-stock has its own distinct badge, the two never combine), and at/below the product's own lowStockThreshold. Neither raw stock nor lowStockThreshold is exposed in the public Product type, only this derived boolean — the public API has no reason to leak exact counts. Shown as a "Nur noch wenige verfügbar" text line (text-warning, the same --color-warning token in globals.css, distinct from the brand-colored discount badge) next to the price on ProductGrid.tsx/ProductSpotlight.tsx/RelatedProducts.tsx/ todo-cards' TodoKartenHero.tsx and Pricing.tsx (both — the page has two independent purchase CTAs, hero and pricing panel, each with their own price/delivery block) and — variant-specific, not "any variant low" — under the product name in CartContent.tsx's own cart line items, plus the existing "(nur noch wenige)" variant-select suffix in AddToCartButton/AddToCartInlineButton. The image-overlaid top-left pill (position: absolute, outside layout flow) now shows only Ausverkauft/discount — low-stock moved off the image into text on request, since a shopper scanning product photos for "-20%" style badges reads a long low-stock sentence pinned to the image as clutter, and a customer already in the cart with that product had no low-stock signal there at all before this. The earlier version of this text line (removed once, see git history) broke equal-height card alignment in ProductGrid.tsx/ RelatedProducts.tsx by only rendering when lowStock was true, so cards with/without the line ended up different heights; this version always renders the line's slot (min-h-[1.05rem], empty when not low-stock) so every card in a row reserves the same space regardless of state — ProductGrid.tsx additionally still has its flex-1 spacer pinning the add-to-cart button to the same Y as before, so the reserved height is belt-and-suspenders there, but load-bearing in RelatedProducts.tsx, which has no such spacer. Only "Ausverkauft" still wins outright over the discount pill, since it replaces it.

Pricing: app/lib/cartTotals.ts's effectivePrice(entry, product) — a selected variant's priceOverride wins over the base product.price (falling back to it when unset or no variant selected). Every cart/ checkout/order-confirmation total (computeSubtotal, computeCartTotals, and each page's own per-line price display in CartContent.tsx, CheckoutContent.tsx, BestellbestaetigungContent.tsx) goes through this instead of reading product.price directly. The checkout route (/api/checkout/route.ts) re-validates the requested variant server-side too — same "never trust the client" reasoning as price re-derivation generally: a line.variant naming something that doesn't exist on that product (removed, or a tampered request) fails the whole checkout rather than silently falling back to the base price. It also re-checks stock at that same point — depth-in-defense, not just the disabled button UI above — rejecting the order when the resolved product/variant has trackInventory on, allowBackorder off, and less stock than the requested quantity.

Snapshotting: orders.items[].variantName captures which variant was picked at order time (same "snapshot, not a live relationship" reasoning as bundleContents) — shown as a parenthetical next to the product name on the order-confirmation email, both invoice PDF types, and the order-detail page. The server-side cart mirror (Customers.cart[].variantName, synced via /api/account/cart) carries the same field so a variant selection survives a login/logout cycle, not just the current session.

See the Payload README's "Inventory & product variants" section for the backend data model (products.variants, stock bookkeeping) this all builds on.

Tracking numbers

orders.carrier/trackingNumber (admin-entered in Payload, no carrier API) show as a clickable link on /konto/bestellungen/[orderNumber] when set — app/lib/tracking.ts's buildTrackingUrl(carrier, trackingNumber) mirrors the Payload backend's own copy of this file byte-for-byte close (same carrier set/URL patterns, kept in sync by hand, no shared package between the two deployments) so the link an admin sees generated in the order-shipped email matches exactly what a customer sees here. Falls back to plain (non-linked) text for carrier: 'other', which has no known URL pattern.

Product bundles & per-product tax rates

Both resolved server-side in /api/checkout/route.ts, at the same point prices are already being re-derived from live Payload data (never trusted from the client):

• Tax rate: product.taxRatePercent ?? companySettings.taxRatePercent — a product's own override if set, otherwise the tenant-wide default from company-settings (fetched alongside the product catalog, Promise.all([fetchProductsBySlug(), getCompanySettings()])). Snapshotted onto orders.items[].taxRatePercent at order creation — see the Payload README's "Per-product tax rates" section for why this has to be a snapshot, not a live lookup.
• Bundles: describeBundleContents() resolves a product's bundleItems (Payload relationship, populated via fetchProductsBySlug()'s depth: 2 fetch — one level deeper than the depth: 1 image alone needs, since bundleItems.product is a relationship nested inside an array field) into a plain string like "2× ToDo-Karten, 1× Wochenplaner", snapshotted onto orders.items[].bundleContents. A bundle is otherwise just a regular product everywhere else in this app — same cart/checkout/ pricing code path, no special-casing needed, since it's just a product with an extra field (see the Payload README's "Product bundles" section for why it's modeled that way instead of a separate collection).

Invoice PDFs

Generated synchronously at checkout and attached to the order confirmation email — not just an on-demand download — per an explicit product decision that a customer should always have the invoice in their inbox, not only in /konto/bestellungen.

• @einfach-produktiv/invoicing — a small standalone package (git.mk360.de/Marco/einfach-produktiv-invoicing, public repo, no secrets in it) holding every invoice/correction-invoice renderer plus computeTaxBreakdown() (see "VAT display" above) and shared formatters, consumed here and by the Payload backend as a git dependency ("@einfach-produktiv/invoicing": "git+https://git.mk360.de/Marco/einfach-produktiv-invoicing.git#main" in package.json). Ships raw TS/TSX source, no build step of its own — this app's next.config.ts lists it under transpilePackages so this app's own bundler compiles it, same as first-party code, the same pattern a monorepo tool like Turborepo uses for internal packages without actually needing a monorepo. Before this package existed (2026-07-23), the correction-invoice renderer was hand-duplicated between this repo and the backend, "kept in sync by eye" — that already caused three real, customer-visible drifts (a silently dropped variantName, a footer that wasn't position: fixed, a numeric vs. spelled-out date format) before the dedup, see that package's own README for the specifics.
• InvoiceDocument — a @react-pdf/renderer Document, not HTML-to-PDF or a headless browser (Puppeteer/Chromium would be a heavier footprint on a VPS already running several other containers). Built-in Helvetica rather than a registered web font — this renders inside a fire-and-forget checkout step, and a font-fetch failure there would be one more way to silently lose the attachment for no real design benefit; brand color/spacing still carries the visual identity via StyleSheet.
• Layout: a header separated by a bold brand-colored rule (not a filled color band — a plain line reads cleaner than a solid block of color across the top) with the wordmark + "RECHNUNG" label, seller/buyer addresses, invoice number/date/order-reference/USt-IdNr. shown as small bordered "meta boxes" rather than a plain text row, a rounded/bordered item table with alternating row shading, and a shaded summary card for the totals — deliberately closer to the site's own card-based UI language than a generic invoice template. The footer is pinned to the bottom of the page (position: absolute + react-pdf's fixed prop), not just wherever the content flow happens to end.
• "Bereits beglichen" badge: shown next to the meta boxes whenever order.paymentMethodTitle is anything other than "Überweisung" (bank transfer) — Kreditkarte and PayPal both settle at checkout, so the invoice says so explicitly (isPaidImmediately(), in the shared package's invoicePdf.tsx — "Überweisung" is the one method named explicitly as the exception, rather than hardcoding a list of "immediate" titles that would need updating every time a new payment method is added in Payload). This one genuinely is conditional on the order's own payment method — unlike bank details below, which just used to be worded as if it were.
• Bank details: company-settings.bankName/.iban/.bic — iban/ bic structured and independently format-validated (uppercased/trimmed on save too, so "de123..." doesn't fail validation just for being lowercase — same normalization discount-codes.code already used), bankName stays free text since there's no fixed format to validate a bank's display name against. Not a single free-text bankDetails textarea anymore, as of the 2026-07-23 e-invoicing migration's Phase 2 — EN16931 wants discrete PaymentMeans data. When iban or bic is set, the footer prints "Bankverbindung: [Bankname ·] IBAN … · BIC …" — always, regardless of the order's payment method. It used to say "Bankverbindung (für Überweisung): …", which read as conditional on paying by bank transfer specifically, but never actually was (the display was only ever gated on whether the field was filled in) — the misleading wording got fixed instead of adding the behavior it implied, since a card/PayPal customer might still want the seller's bank details for other reasons (e.g. a refund).
• Per-tax-rate summary: line items are grouped by their own snapshotted taxRatePercent (see the Payload README's "Per-product tax rates" section) via the shared package's computeTaxBreakdown() (see "VAT display" above) and the summary prints one plain "Netto" / "zzgl. X% MwSt." pair per distinct rate actually present in that order — no % after "Netto" itself anymore, since the rate is already stated on the "zzgl." line directly below it. A plain single pair in the common case (one rate for the whole order), a real multi-rate breakdown the moment a product with a different rate is involved. The order-level discount/ shipping are distributed proportionally across each rate group before computing net/tax, so the grouped totals still reconcile exactly to order.total.
• Product thumbnails: each item row shows a small product image — resolved from the order-confirmation data's already-available imageUrl for the checkout-time attachment, or via getProductImagesByIds() (see "VAT display" above) for the on-demand re-download route, since a stored order item only snapshots a numeric product id, not an image URL.
• Bundle contents: an item row for a bundle product also shows the small muted bundleContents sub-line snapshotted at order time (see the Payload README's "Product bundles" section).
• Shipping address: when order.hasDifferentShippingAddress is set (see "Optional deviating shipping address" above), a third "Lieferadresse" address block joins Von/An (three ~30%-width columns instead of two ~45%-width ones) — otherwise unchanged, two columns as before. USt-IdNr. no longer repeats in a header meta box — it already lives in the footer, printing it twice was redundant.
• app/lib/invoiceData.ts (still local to this repo — a thin server-only wrapper, not part of the shared package) — generateInvoicePdf(order, seller) / generateCorrectionInvoicePdf(kind, order, seller), the render entrypoints every caller below goes through; both just call straight into @einfach-produktiv/invoicing's renderInvoicePdf()/ renderCorrectionInvoicePdf(). seller (company-settings data) is passed in rather than fetched inside these functions, so a caller that also needs it for something else in the same request (e.g. orderEmail.ts's legal email footer, see "Legal footer (Anbieterkennzeichnung) on every email" below) fetches it once via getSellerForInvoice(), not twice.
• Original invoice — called from two places, same render function: app/lib/orderEmail.ts (checkout attachment — a PDF-generation failure here does not sink the confirmation email itself, it just sends without the attachment and alerts admin) and app/api/account/orders/[orderNumber]/invoice/route.ts (GET, customer's own order only, "Rechnung herunterladen" on /konto/bestellungen/[orderNumber]) — a re-download always matches what was originally emailed, since invoiceNumber/invoiceIssuedAt are assigned exactly once, server-side, at order creation (Payload's orders.ts beforeChange hook — see the Payload README) and never regenerated.
• Correction invoice (Stornorechnung/Gutschrift) — same "no file storage" approach. The real document is generated once, Payload-side, the moment an order reaches cancelled/returned (see the Payload README's "How a Stornorechnung/Gutschrift relates to the original invoice" section for the full legal/mechanical reasoning) and attached to that status email. This repo's own /konto/bestellungen/[orderNumber] "Stornorechnung/Gutschrift herunterladen" button (app/api/account/orders/[orderNumber]/correction-invoice/route.ts) calls the exact same renderCorrectionInvoicePdf() from @einfach-produktiv/invoicing the backend used to generate the original — not a ported approximation anymore (that used to be a separate, hand-duplicated copy; see the shared package's README) — so a re-download is now structurally guaranteed to match what was emailed, not just guaranteed by careful manual syncing. No PDF is ever persisted to disk/S3/Media: correctionInvoiceNumber/correctionInvoiceIssuedAt are immutable once set (Payload's beforeChange hook), so re-rendering from the order's own stored data always reproduces the identical document — the underlying data is already durable in Postgres, and deterministic regeneration needs no cleanup or storage cost, same reasoning already applied to the original invoice. Also has product thumbnails (same resolution approach as the original invoice) and, for a Stornorechnung specifically, an explicit "Versand" summary line — it was previously only folded silently into the tax-rate groups' scaled gross amounts, with no line stating how much of the reversed total was shipping. A Gutschrift never shows this line, since it never reverses shipping in the first place (see the reasoning below).
• Numbering: invoiceNumber and correctionInvoiceNumber each come from their own gapless counter on Payload's number-ranges collection (invoicePrefix/Next/Padding vs. correctionInvoicePrefix/Next/ Padding — a Stornorechnung/Gutschrift used to draw from the same counter as ordinary invoices; split into its own sequence as of 2026-07-23). Both are assigned via a single atomic UPDATE ... RETURNING against Postgres (Payload's backend numberRange.ts), not a read-then-write across two separate calls — see the Payload README's "Number ranges" section for why that distinction actually matters for §14 UStG.
• company-settings (Payload collection, structured seller data — name/address/vatId/taxRatePercent/bankName/iban/bic) is fetched via getCompanySettings()/getSellerForInvoice(), authenticated the same way as order creation (x-order-service-secret header, ORDER_SERVICE_SECRET) since it's not public-read (holds bank details) but does need to be reachable from this app's own server-side code, not just from inside Payload's admin. Currently seeded with placeholder data ("Björn Wendt", "Musterstraße 12", USt-IdNr. "DE123456789", a placeholder IBAN/BIC) mirroring the Impressum's own placeholder content — real business details need to be entered in the Payload admin before an invoice generated from this is legally valid. taxRatePercent is deliberately a configurable admin field, not a hardcoded 19 in the renderer, per an explicit decision to keep the VAT rate editable without a code change.
• §14 UStG line items: seller/buyer address, invoice number + date, order reference, per-item quantity/price, net subtotal per rate, tax rate + amount per rate, gross total — all on the PDF, not just the summary the confirmation email's HTML already shows.
• E-invoicing (ZUGFeRD/EN16931) migration — in progress as of 2026-07-23. Everything above is still a plain PDF; the shared package's README and the memory notes behind this project track the phased plan (hybrid PDF/A-3 + embedded XML via @e-invoice-eu/core, applied to every invoice, not just B2B) — not yet built as of this writing.

Company Settings & Live Preview

company-settings has a Live Preview button too, like email-templates — but instead of an HTML page, it's a live, in-browser rendered PDF: opening the document in the Payload admin shows the actual invoice layout updating as the admin edits sellerName/address/taxRatePercent/ bankName/iban/bic, no save required.

• app/company-settings-preview/page.tsx + components/LiveCompanySettingsPreviewClient.tsx — same entrypoint pattern as /email-preview/[type] (Draft Mode via app/api/preview/route.ts), but no [type] segment — there's only one kind of document here, unlike the 6 email types. Actually gated on draftMode().isEnabled (calls notFound() otherwise), unlike /email-preview — this data includes a real bank IBAN/address once filled in, not just marketing email copy, so it must not render for an unauthenticated visitor who happens to find the URL.
• @react-pdf/renderer's <PDFViewer> (not renderToBuffer()) is what makes this a live preview rather than a static download — it's a browser-only component that renders a Document straight into an embedded PDF viewer <iframe>, re-rendering whenever its props change. Paired with useLivePreview()'s live data (same postMessage mechanism as the email templates preview), editing a field in the admin re-renders the actual PDF in real time — no server round-trip per keystroke. Dynamically imported with { ssr: false } (next/dynamic) since it touches the DOM directly; the HTML-string email previews elsewhere don't need that since they're just dangerouslySetInnerHTML.
• Renders InvoiceDocument (exported from @einfach-produktiv/invoicing specifically for this — everywhere else only the async renderInvoicePdf() buffer-generator is used) against a fixed SAMPLE_INVOICE_ORDER (also exported from that same package) — same "no real document to preview against generically" reasoning as email-templates' own SAMPLE_ORDER.
• No draft/published distinction here, unlike email-templates: company-settings has no content-versioning concept, it's just the current row — the page's initial (pre-postMessage) fetch is the same live data getCompanySettings() always returns.

Orders & customer accounts

An account is required to buy — there is no guest checkout. Registration happens inline in /checkout's "1. Rechnungsadresse" card (a password field appears there when nobody's logged in). There's no persistent "already a customer? log in" prompt — that was gendered ("Schon Kundin?") and shown to every logged-out visitor regardless of relevance. Instead, the email field's onBlur calls /api/account/check-email (checkEmailExists() in customerAuth.ts, service-secret authenticated — Customers isn't public-read) and only then swaps Card 1's password field out for an inline login form, gender-neutral copy, pre-filled with the email just typed. handleSubmit's own emailExists handling (see "Checkout registration collisions" below) is the fallback for the case this check was skipped or raced.

• app/lib/customerAuth.ts (server-only) is the single place that talks to Payload's customers collection — a second, fully separate auth: true collection from any admin login, existing purely for this storefront's own accounts. Payload issues a JWT on register/login; this app never relies on Payload's own auth cookie (different origin — einfach-produktiv.mk360.de vs payload.mk360.de) and instead mints its own httpOnly ep_customer_token cookie holding that JWT, forwarded as an Authorization: JWT <token> header on every subsequent Payload call.
• app/api/account/* — thin route handlers around customerAuth.ts: register, login, logout, me, orders (list), profile (GET/PATCH incl. the one saved default address), password (verifies the current password via a real login attempt before changing it, doesn't just trust the caller), cart (GET/POST, see below), verify-email, resend-verification, delete, export (see "Email verification" and "GDPR self-service" below), forgot-password, reset-password (see "Password reset" below), orders/[orderNumber] (PATCH — cancel/return-request, see "Order cancellation & returns" below), and orders/[orderNumber]/invoice (GET — invoice PDF download, see "Invoice PDFs" below).
• /konto/bestellungen lists a customer's own orders (status shown as a colored OrderStatusBadge.tsx, plus an "Abmelden" link — LogoutButton.tsx); /konto/bestellungen/[orderNumber] shows one order's full detail (items, address, totals, status). status (received → processing → shipped → delivered, plus cancelled/return_requested/returned) is maintained by hand in the Payload admin for the shipping states — no shipping-carrier API integration.
• Navbar.tsx's AccountLink (account icon, always visible in the header itself — not duplicated inside the mobile fullscreen menu, see "Mobile navigation" below) is the only always-reachable way into /konto/* — added after discovering there previously wasn't one: /checkout's own login toggle only renders once the cart already has items (its empty-cart state is an early return with no such toggle), and /bestellbestaetigung's "Meine Bestellungen ansehen" link only exists after a completed order. A returning customer with an empty cart and no recent order had no way to reach the login page at all before this. Fetches auth state client-side via /api/account/me (not through the server-rendered root layout) specifically so app/layout.tsx — otherwise static/ISR-cacheable — doesn't get forced into per-request dynamic rendering just to know one icon's href; briefly shows the logged-out state on first paint until that fetch resolves. Re-fetches on an ep-auth-changed window event (app/lib/auth.ts's dispatchAuthChanged(), called by every login/logout/checkout-registration call site) — the icon otherwise never noticed a login/logout until a hard reload, since router.refresh() only re-runs Server Components, not an already-mounted Client Component's effects, and this Navbar lives in the root layout and never unmounts across navigations. The icon itself also gets a small brand-colored underline while logged in — same visual language as the desktop nav links' active-state indicator — since the icon alone doesn't otherwise signal session state at a glance.

Mobile navigation

Below lg (1024px), the hamburger opens a fullscreen panel (Navbar.tsx, motion.div from the motion/react package already used elsewhere in this app for NewsletterModal/VersandModal) — not an in-flow accordion pushed under the header like before. A circular clip-path reveal (circle(0vmax at 100% 0%) → circle(150vmax at 100% 0%), vmax rather than % so full coverage holds regardless of aspect ratio) expands from the hamburger's own top-right corner, sweeping toward the opposite corner last. Nav links fade/rise in with a per-item stagger once the reveal has visibly opened up. The panel is a sibling of <header>, not a child — mobileOpen gives the header its own backdrop-blur, which would make it a new CSS containing block for any position: fixed descendant and break the panel's fixed-to-viewport positioning (same class of bug documented on NewsletterModal). No login/account CTA inside the panel — that's reachable via the account icon in the header itself, which stays visible above the panel throughout.

• Checkout registration collisions: if the email typed into Card 1 during inline registration already belongs to an existing account, Payload's create call fails — registerCustomer() in customerAuth.ts detects this specifically (emailExists: true on the returned AuthResult, inferred from the field flagged in Payload's validation error, since Payload's own message text doesn't distinguish "duplicate" from other email-field failures) rather than just surfacing a generic error. CheckoutContent.tsx's handleSubmit reacts by switching straight to the login toggle with that email pre-filled and scroll-into-view, instead of leaving the customer stuck with an error and no obvious next step.
• /konto/profil edits name + the one saved default address (deliberately a single address, not a full address book — see the assistant's memory note on optionally expanding this later), changes the password, shows the email-verification banner, and has the GDPR export/delete section.
• Cart sync: app/components/CartSync.tsx (mounted once in app/layout.tsx) watches the local cart via useCart() and debounce-POSTs it to /api/account/cart on every change; the route 401s (silently, by design) when nobody's logged in. On login (LoginForm.tsx, and CheckoutContent.tsx's inline toggle), mergeServerCartIntoLocal() (app/lib/cart.ts) folds whatever was saved server-side into the local cart by quantity — CartSync's own effect then pushes the merged result back up on its own, so there's no separate explicit "save after merge" call.
• Still out of scope: a full address book (single default address only — see the assistant's memory note), single-currency.

Rate limiting

app/lib/rateLimit.ts — an in-memory, per-IP sliding-window limiter (checkRateLimit(key, {limit, windowMs})), deliberately no Redis: this app runs as a single Coolify container, so a plain Map is enough and needs no new infra. Resets on redeploy/restart — acceptable at this shop's traffic level; revisit with a shared store if this ever scales to multiple instances. Applied (keyed by X-Forwarded-For, which Caddy already sets) to /api/account/register, /api/account/login, /api/account/password, and /api/account/resend-verification.

This complements, not replaces, Payload's own per-account login lockout (customers.auth, maxLoginAttempts: 5 / lockTime: 10min, Payload defaults — see the Payload README's "Login rate limiting" section) — that stops brute-forcing one known email, this stops an IP spraying attempts across many, or hammering registration.

Session refresh

proxy.ts (project root — Next.js 16 renamed middleware.ts to proxy.ts; see node_modules/next/dist/docs/01-app/03-api-reference/03-file-conventions/proxy.md if this ever looks wrong against older docs/training data). Runs on /checkout, /konto/*, /api/account/*. Decodes (not verifies — Payload verifies for real on every actual API call) the ep_customer_token cookie's JWT exp claim; if less than 15 minutes remain, silently calls Payload's built-in POST /api/customers/refresh-token and swaps in the refreshed token. Net effect: an actively-browsing customer never gets logged out mid-session, but someone who walks away is logged out within ~2h of their last request (Payload's tokenExpiration default, unchanged on the Payload side).

Email verification

Non-blocking by design — see the Payload README's customers.emailVerified section for why this is a custom flag rather than Payload's built-in auth.verify: true (short version: that would hard-block login for a brand-new customer trying to finish the purchase they just registered mid-checkout for). The initial email is sent by Payload itself (an afterChange hook on customers, fires on create). /konto/profil's VerificationBanner.tsx shows a non-blocking "bitte bestätigen" hint with a resend link when !profile.emailVerified; resending (/api/account/resend-verification) is sent directly from this app instead (app/lib/alertAdmin.ts's sendVerificationEmail() — same Hostinger SMTP, no Payload hook to piggyback on for a plain field update).

Password reset

Unlike email verification, this needed no custom flag — forgotPassword doesn't block login, so it's Payload's built-in flow as-is (see the Payload README's customers.auth.forgotPassword section), just with the email content/destination swapped so the link points here instead of the Payload admin. /konto/passwort-vergessen (ForgotPasswordForm.tsx) → POST /api/account/forgot-password → always responds {ok:true} regardless of whether the email exists (same anti-enumeration reasoning as Payload's own operation — the route must not leak a different response shape for "no such account", see its own comment). /konto/passwort-zuruecksetzen?token=... (ResetPasswordForm.tsx, token read server-side from searchParams — avoids needing a <Suspense> boundary, unlike the ?code= cart case above which genuinely needs client-side useSearchParams()) → POST /api/account/reset-password → Payload logs the customer in on a successful reset (returns the same {token, user} shape as login), so the session cookie is set immediately, no separate login step. LoginForm.tsx links to /konto/passwort-vergessen.

Email templates & Live Preview

All 6 transactional emails (order confirmation, password reset, and the 4 status-change types below) read their subject/heading/body/footer wording from Payload's email-templates collection — editable in the admin without a deploy, with a Live Preview button using the exact same mechanism as Posts/LegalPages/Testimonials (useLivePreview() from @payloadcms/live-preview-react, already a dependency here for LivePostContent.tsx).

• app/lib/emailTemplates.ts — pure string-building functions (renderOrderConfirmationHtml(), renderPasswordResetHtml(), renderOrderStatusHtml()), no server-only or client-only imports. Used both server-side for the real send (orderEmail.ts) and client-side for the Live Preview page — same function, same inputs, so a Live Preview edit and the real sent email are guaranteed to render identically for order-confirmation, the only one of the 6 actually sent from this repo (password-reset and all 4 status-change types are sent by Payload itself, using its own inline templates — see that repo's README for why — so their Live Previews approximate rather than pixel-match). Inline-styled HTML (<table> layout, style attributes, no Tailwind/<style> block) — most email clients strip external/embedded CSS.
• /email-preview/[type]/page.tsx — entered exclusively from Payload's admin iframe (EmailTemplates.ts's admin.livePreview.url), never a real visitor destination (noindex). Always reads with draft: true so an unsaved admin edit shows immediately. Renders against sample data (SAMPLE_ORDER in emailTemplates.ts) — unlike the other three Live Preview targets, there's no "current" real order/reset-link to preview against generically.
• The real send always reads the published template (getEmailTemplate() in app/lib/payload.ts, draft unset) — a Live Preview edit never affects a live customer email until actually saved.
• npx payload run src/seed-email-templates.ts (Payload repo) seeds defaults for all 6 rows — deliberately on-brand and a little playful ("Bestellt!" / "Kein Drama." / "Unterwegs!" / "Storniert." / "Alles klar." / "Alles erledigt.", not generic transactional-email boilerplate), matching this site's voice elsewhere (see e.g. the testimonial copy). Two intentional exceptions to that voice: the email-verification mail (Payload-side, plain functional copy — see that README) and the Stornorechnung/Gutschrift PDFs (formal legal documents, no brand voice by design). Editable in the admin afterward regardless. sendOrderConfirmationEmail() also has a hardcoded fallback for the rare case a fresh install's order arrives before that seed has run.
• emailShell()'s visual design deliberately echoes /bestellbestaetigung (the on-screen order confirmation page) rather than reading as a generic transactional email: same warm cream background/brand color as globals.css's --color-* tokens (hardcoded here as literal hex — email clients don't resolve var() either), a circular brand-tinted icon (✓ for order-confirmation, ✉ for password-reset) echoing that page's own success-icon treatment, a thin brand-colored divider under the heading, and a Georgia/serif heading font as the closest reliably-available approximation of the site's Playfair Display (most email clients strip @font-face/external font requests, so an actual web font isn't an option here). Not shared code with the React page — this is plain inline-styled HTML built for email-client compatibility (nested <table>s, no flexbox) — just matched by eye.
• Footer carries a full legal Anbieterkennzeichnung, not just a brand line. emailShell() takes a footerLines: string[] array built by buildLegalFooterLines(seller) — sellerName, sellerStreet, sellerZip/sellerCity (+ sellerCountry if not Germany), E-Mail: sellerEmail, and USt-IdNr.: vatId when set — the same admin-editable company-settings fields the invoice PDFs already use, rather than a literal "einfach produktiv · admin@mk360.de" string. orderEmail.ts and alertAdmin.ts (both the resend-verification mail and the plain-text critical-alert mail) all fetch company-settings once (getSellerForInvoice()) and pass the seller object straight into the render functions, which call buildLegalFooterLines() themselves — one place composes the footer, not each call site. The Payload-side sends (password-reset, the 4 status-change emails, the initial verification email) get the equivalent treatment via that repo's own src/lib/sellerInfo.ts's buildLegalFooterLines()/getSellerFooterLines() — see that repo's README for its own copy of this section. Live Preview passes seller: null, which falls back to DEFAULT_LEGAL_FOOTER_LINES (a placeholder Anbieterkennzeichnung) since there's no real order/tenant context there to fetch against. Note company-settings currently has no Handelsregister court/number or Geschäftsführer field — fine for a sole proprietorship, but would need adding if the business becomes a registered legal form (GmbH etc.), see that collection's own field list above.
• From display name is dynamic (seller.sellerName), the address itself stays admin@mk360.de. Reply-To is set to seller.sellerEmail so a customer's reply actually reaches the seller regardless of the From address. The address isn't also switched to sellerEmail because that domain isn't confirmed SPF-authorized on the Hostinger account backing admin@mk360.de yet — doing so without that confirmation risks order-confirmation/verification mail landing in spam or bouncing outright. Both orderEmail.ts and alertAdmin.ts's sendVerificationEmail set this the same way; sendCriticalAlert (internal, admin@mk360.de to itself) doesn't need it.

GDPR self-service

/konto/profil's "Konto & Daten" section:

• Export (/api/account/export, GET) — profile + every order's full detail as one downloadable JSON (Content-Disposition: attachment). Genuinely complete, not a summary — Art. 20 data portability.
• Delete (/api/account/delete, POST, password re-verified via a real login attempt first) — deletes the customers document. Past orders are not touched: orders.customer is ON DELETE SET NULL in Payload, so an order keeps its own name/address/items snapshot (already stored independently for exactly this kind of reason) for tax-retention purposes (§147 AO / GDPR Art. 17(3)(b) explicitly permits this) — only the account/login itself disappears. The UI says this explicitly before deleting, not as a surprise afterward.

Order cancellation & returns

/konto/bestellungen/[orderNumber] shows one self-service button when applicable: "Bestellung stornieren" while status === 'received', or "Rücksendung anfragen" while status is 'shipped' or 'delivered' (customerOrderAction() in customerAuth.ts decides which, if any). Posts to /api/account/orders/[orderNumber] (PATCH), which re-checks the transition is still valid (friendlier error than a bare 403 if it's gone stale — two tabs open, order shipped in the meantime) before calling requestOrderStatusChange().

Requesting a return opens an inline form (OrderActionButton.tsx), not just a confirm dialog — partial returns are supported: a quantity input per order line (0 up to that line's ordered quantity) plus a required reason textarea. At least one line must have a nonzero quantity to submit. Cancel stays a plain window.confirm() — it's a lower-stakes, whole-order-only action (before shipping, often just a change of mind), no quantity picker or reason needed there.

The route (/api/account/orders/[orderNumber] PATCH) reconstructs the order's full items array before sending it to Payload — only the requested lines' returnQuantity differs from what's already stored, every other field (product/price/tax rate/etc.) is passed through unchanged. This isn't optional: Payload's array field expects every required sub-field present on each row, and the field-lock hook (see below) specifically checks that only returnQuantity changed — a sparse { returnQuantity: 2 }-only patch would fail both.

The real security boundary is in Payload, not here: orders.access.update already scoped a customer's JWT to their own order, but with no field-level restriction — before this stage, a logged-in customer could in principle PATCH any field of their own order (total, items, anything), just because nothing in the frontend had ever exercised that path yet. Orders.ts's beforeChange hook rejects a customer-authenticated update unless the change is limited to status (plus returnReason and each item's returnQuantity, bounded 0..quantity, alongside a return_requested transition), via an allowed transition. See the Payload README's own writeup for the full detail — including orderUpdateValidation.ts, where this logic now lives as a unit-tested pure function.

No hard 14-day return-window check in code (no separately tracked delivery date exists yet) — relies on the existing /widerruf legal text plus manual admin review. No automatic refund (no payment provider exists yet) — a return/cancellation request is just captured structurally instead of arriving by email/phone; the admin still processes it by hand in the Payload admin.

Reaching status: 'cancelled' or status: 'returned' also auto-generates a Stornorechnung/Gutschrift correction-invoice PDF, attached to that status's customer email (Payload-side, see the Payload README's "How a Stornorechnung/Gutschrift relates to the original invoice" section — this is not frontend code). Stornorechnung is always a full reversal (cancellation is always pre-shipping, whole order, shipping included). Gutschrift reflects only the returned quantities — full or partial — excludes shipping (already delivered by the time a return is possible) and never reprorates the original discount (confirmed policy, not a default: the discount stays with whatever's kept). Either way, this is a document only, not a money movement: an actual refund still has to happen manually, since no payment provider exists yet to capture or reverse a real charge.

Status-change emails

Four orders.status transitions trigger a customer email — shipped, cancelled, return_requested, returned (deliberately not delivered, redundant with the carrier's own notification; not processing/received, not customer-actionable). Sent entirely from Payload, not this repo — orders.ts's afterChange hook there compares doc.status to previousDoc.status and fires regardless of who made the change (an admin setting shipped/returned in the Payload admin, or the customer's own self-service cancel/return-request above land on the exact same hook). See the Payload README's orders.ts section for the actual send logic, including the Stornorechnung/Gutschrift attachment on cancelled/returned.

This repo's only involvement is the Live Preview approximation — same established gap as password-reset (see below): renderOrderStatusHtml() in app/lib/emailTemplates.ts and the corresponding entries in /email-preview/[type]'s VALID_TYPES exist purely so an admin editing order-shipped/order-cancelled/order-return-requested/order-returned in the email-templates collection sees a reasonable preview — the actual sent HTML is Payload's own src/lib/emailShell.ts render, not this file's.

Monitoring & alerting

Base uptime (is the site/Payload reachable at all) is already covered by existing Uptime Kuma HTTP monitors with email alerting (monitor.mk360.de — see ~/dev/README.md's Kuma section) and isn't part of this app. What's new here is the one failure mode Kuma structurally can't see: the site is up, a customer completes checkout, and the order still doesn't get persisted (createOrder() returns null in /api/checkout/route.ts). That path calls app/lib/alertAdmin.ts's sendCriticalAlert() — its own, independent SMTP connection (same Hostinger account, but not routed through Payload, since Payload being the actual problem is one of the scenarios this needs to still report on). Fire-and-forget, its own try/catch, never blocks or fails the actual error response the customer sees.

/api/health (GET) — checks Payload's public API is actually reachable (3s timeout), not just that this page rendered; added as a Kuma HTTP monitor in the existing "Content & API" group (~/dev/README.md's documented sqlite3-insert method, Kuma 1.x has no REST API for this).

/shop itself also has its own Kuma HTTP monitor ("einfach-produktiv Shop (Produkte, Varianten, Lagerbestand)", same "Content & API" group) — added once the shop grid started doing real work at render time (fullyOutOfStock across a product's variants, effectivePrice()), not just listing static content; /api/health alone only proves Payload is reachable, not that this specific page still renders. The Payload jobs queue's own failure monitor (/api/health/jobs, hasError: true in the last 24h) already covers all five scheduled jobs generically by task-agnostic query — the four added this session (low-stock digest, stale-unverified-accounts report, weekly revenue report, expired-discount-code cleanup) needed no monitor changes of their own; see the Payload README's "Jobs Queue" section.

Tests

npm run test:unit (Vitest, node environment, no jsdom/Next.js runtime needed) — no test infrastructure existed in this repo before; started with the pure logic most likely to silently produce wrong numbers on a live order, not attempted exhaustive coverage:

• app/lib/__tests__/cartTotals.test.ts — subtotal/discount/shipping math (computeSubtotal, computeCartTotals), incl. the fixed-discount clamp and compareAtPrice-based savings display being independent of the discount-code math.
• app/lib/__tests__/bundleContents.test.ts — describeBundleContents(), extracted out of app/api/checkout/route.ts into its own module (app/lib/bundleContents.ts) specifically so it's importable from a test — Next.js route.ts files only allow HTTP-method (+ a few config) exports, not arbitrary named ones.

The original invoice's isPaidImmediately()/groupByTaxRate() and the Gutschrift/Stornorechnung money math (resolveLineItems(), groupByTaxRate()) both live in @einfach-produktiv/invoicing now (see "Invoice PDFs" above), not in this repo — their tests moved with them into that package's own src/__tests__/, run via that package's own vitest, not this repo's test:unit. The Payload-side orders.ts field-lock security logic is still tested in the Payload backend's own test:unit — see that repo's README's own "Tests" section, since that's where that logic actually lives.

Deployment

• Dockerfile: 3-stage build (deps → builder → runner) with BuildKit cache mounts, producing a ~100 MB standalone image. This is the reference Dockerfile copied when scaffolding new projects on this VPS (see the infra repo's new-project workflow).
• Deploys via git push → Gitea webhook → Caddy /deploy/einfach-produktiv bridge → Coolify API → rebuild + restart. Full mechanics in ~/dev/README.md.

Related design source

• ~/dev/einfach-produktiv/mockups/ — Figma-stage mockup PNGs
• ~/dev/einfach-produktiv/styleguide.md — design tokens (colors, type, spacing)
• ~/dev/einfach-produktiv/einfachproduktiv_figma_prompt_guide_v3.md — Figma rebuild prompt guide