Invoices for your Bolt app

Bolt builds the checkout, not the invoice

With Bolt you can build an app in minutes and turn on Stripe in one click, including webhook processing for payments and subscriptions. What's missing afterwards: Bolt creates a payment, but not an invoice in the sense of German law. There's no structured document under EN 16931, no GoBD archive (GoBD being the German rules for keeping digital records), no VAT logic per country and no DATEV export.

Rechnungskit closes that gap where Bolt already handles the payment: in the Supabase Edge Function behind your Stripe webhook. One API call turns the sale into a ZUGFeRD invoice with your own number sequence, archived in an audit-proof way and ready for booking in DATEV.

Why Bolt is a good fit

Bolt generates a real full-stack app: a React frontend plus server-side functions based on Supabase Edge Functions, along with the native Stripe connection and its webhooks. That's the environment the connection needs: a server-side function where your API key is stored safely and where you add a call to Rechnungskit when a checkout succeeds. You don't build new infrastructure; you use what Bolt has already set up.

The call you add

In the Edge Function that processes your Stripe webhook, add a fetch to POST /v1/orders in the success branch. Amounts go in whole cents, the Stripe payment reference goes in paymentRef, and the key comes from the secrets:

// Supabase Edge Function (Bolt), in the Stripe webhook after a successful payment
const res = await fetch('https://api.rechnungskit.de/v1/orders', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${Deno.env.get('RECHNUNGSKIT_API_KEY')}`,
    'Content-Type': 'application/json',
    'Idempotency-Key': session.id
  },
  body: JSON.stringify({
    orderNo: session.id,
    paymentRef: session.payment_intent, // pi_... from Stripe
    email: session.customer_details?.email,
    billingAddress: {
      name: session.customer_details?.name,
      country_code: session.customer_details?.address?.country, // required for VAT
      postal_code: session.customer_details?.address?.postal_code,
      city: session.customer_details?.address?.city,
      street: session.customer_details?.address?.line1
    },
    items: [{ name: 'Pro plan', quantity: 1, unitGrossCents: 2900, taxRate: 19 }]
  })
})

One thing to know about Bolt: check that your function verifies the webhook's Stripe signature before it derives an order. According to the Bolt docs, the Stripe integration does this automatically, but after changes to the generated code it is worth a look. On the Rechnungskit side this is covered, because Rechnungskit verifies the signature of the Stripe payment itself when it comes in.

Where does the API key come from?

You create the key in Rechnungskit under Connections → API (directly at app.rechnungskit.de/settings/api) with the orders:write permission. It's shown exactly once. Store the value in Bolt or Supabase as a secret (for example RECHNUNGSKIT_API_KEY), never in the frontend, and read it in the Edge Function with Deno.env.get('RECHNUNGSKIT_API_KEY').

One-time setup, stated plainly

The code is simple, but you set up a few things once:

• Connect Stripe in the dashboard and set it to API. You connect your Stripe account once in Rechnungskit under Connections → Connect, with API orders as the sales basis. It's a click, not code.
• Send the country code. Without country_code in the billing address the order is rejected, because the VAT can't be determined otherwise.
• Set an Idempotency-Key. Every POST needs the header; otherwise a duplicate webhook creates two orders. The Stripe session ID is a good value.
• Check the Stripe signature in Bolt. Make sure your function verifies the webhook before it derives the order.
• Retry on 5xx. Retry the call after a short pause so no order gets lost.

Show your AI the docs

Rechnungskit publishes a complete OpenAPI 3.1 specification at api.rechnungskit.de/v1/openapi.json. Give it to Bolt's AI and ask it to report an order to Rechnungskit in the Stripe webhook after a successful payment. The full reference with working examples is in the API documentation. Building with Lovable, Replit or v0 instead? It works the same way, see invoices for no-code and AI app builders.