E-invoicing for SaaS: a compliant invoice from every subscription payment

Your billing tool only makes a PDF

Stripe Billing is good at collecting recurring payments. What it issues afterwards, though, is a PDF, not an e-invoice in the German legal sense. Stripe itself points to partner apps for sending e-invoices. In German B2B business, every company has had to be able to receive e-invoices since 2025; you have to issue them for sales from 2027 (with prior-year revenue above 800,000 euros), otherwise from 2028 (§ 27(38) UStG); details on the e-invoicing mandate 2027 page. German bookkeeping is then missing its most important step: turning the subscription payment into a structured, machine-readable document under EN 16931, archiving it to GoBD standards (the German rules for tamper-proof records) and preparing the DATEV export.

Rechnungskit fills that gap. You connect your billing system once, and every subscription charge automatically becomes a ZUGFeRD invoice with your own number range. There are three routes: Stripe Billing as a direct connection, subscriptions run in Rechnungskit with their own subscription link, or your own API, where you create orders and connect the payment provider (Stripe, Mollie, PayPal, GoCardless or Unzer) for matching. In every case we take the line items, VAT rates and service period rather than a finished PDF, so the result is a real invoice and not a converted copy.

Two routes with Stripe, one e-invoice

Whether you keep Stripe Billing or run your subscriptions in Rechnungskit only decides who manages the subscription. Either way, the money goes through your own Stripe account, and every period becomes the same e-invoice with your number range.

Stripe · with or without Stripe Billing

Who does what?

Keep Stripe BillingRoute 1

Subscription managed byStripe Billing

Payment collected byStripe

InvoiceRechnungskit, as soon as Stripe reports the subscription invoice as paid with line items, VAT rates and service period

Stripe invoice emailsturn off once otherwise your customer gets two invoices

Cancellation, payment methodthrough Stripe

A good fit ifyou already have a Stripe setup running, including usage-based pricing or several line items

Rechnungskit subscriptionsRoute 2

Subscription managed byRechnungskit, through a subscription link checkout.rechnungskit.de/s/…

Payment collected byyour Stripe account or Mollie, card or SEPA no Stripe Billing needed

InvoiceRechnungskit, with every charge

Seats, add-ons, upgradesprorated by the day supplementary invoice under § 31 UStDV, credit note under § 17 UStG

Cancellation, withdrawalcustomer portal with a cancellation button and a withdrawal button § 312k and § 356a BGB

A good fit ifyou sell monthly or annual plans and want subscription, invoice and customer portal in one place

You can switch from route 1 to route 2 without contacting your customers. The takeover from Stripe Billing uses the payment mandates already stored in your Stripe account, so your customers do not sign up again or re-enter their card.

What the subscription checkout looks like for your customers

For route 2, every plan gets a shareable subscription link that you can put on your pricing page, in your app or in a newsletter. There, your customer picks the quantity, private person or business, and a payment method. Rechnungskit handles the rest, from the charge to the invoice.

The service period SaaS depends on

A SaaS subscription is a service delivered over a period of time. Rechnungskit takes the service period (Leistungszeitraum) straight from the subscription charge and writes it on the invoice and, in structured form, into the e-invoice. For an annual plan whose period runs past the invoice month, the DATEV export can book deferred revenue (pRAP, § 250(2) HGB) across the months it belongs to, monthly or by the day and across the turn of the year. This requires that you prepare a balance sheet and that the pRAP account has been set up with your tax advisor; with cash-basis accounting (Einnahmen-Überschuss-Rechnung), no deferral is needed.

SaaS VAT: OSS, reverse charge and non-EU countries

VAT on a software subscription comes down to two questions. Is your customer a private person (B2C) or a business with a VAT ID (B2B)? And are they in Germany, elsewhere in the EU or outside the EU? That gives six cases. The most common mistake is to think OSS applies to everyone, when it only covers B2C. For B2B in the EU, the reverse charge applies instead.

Legal basis of the matrix: § 3a(2) and (5) UStG (place of supply), § 14a(1) UStG (reverse charge note), § 18a UStG (EC Sales List), § 18j UStG (OSS).

How does Rechnungskit know whether a sale is B2C or B2B? From the VAT ID, not the company name. If a VAT ID is present and confirmed by the BZSt in a qualified check, the customer is treated as a business and the sale goes through the reverse charge. Without a VAT ID, or with an unverified one, Rechnungskit treats the sale as B2C and charges VAT. An unclear case becomes a review task, never a silent tax exemption. With Stripe Billing, the VAT ID comes from the tax IDs of your Stripe customer; with your own API, you pass it in the vat_id field of the billing address.

Rechnungskit makes this decision automatically for each invoice. For B2C sales in the EU, it takes the VAT rate per destination country from the EU's TEDB database and monitors the shared €10,000 threshold (including your earlier sales if you switch mid-year) for the OSS return. For B2B sales in the EU, it runs a qualified VAT ID check with the BZSt, issues a net invoice with the reverse charge note and prepares the EC Sales List. The threshold only concerns B2C and is one shared limit for digital services and physical distance sales; there is no extra allowance for SaaS.

One step you must not forget

If you keep using Stripe Billing (route 1), Stripe sends its own invoice email for every subscription payment. If that stays switched on, your customer gets two invoices for the same purchase: Stripe's and the tax-valid one from Rechnungskit. So you turn off Stripe's own invoice emails once. Rechnungskit reminds you about this step right at the Stripe connection and again at go-live, and links to the right place in the Stripe dashboard. The connector page explains how the Stripe integration works in detail.