Verifactu Billing for SaaS with Stripe: How to Comply Without Touching Your Codebase

#You have a SaaS billing 50.000 € per month with Stripe. Everything works perfectly. But in 2027 you can be fined up to 150.000 € if you don’t comply with Verifactu.

This is not an exaggeration. It’s the penalty regime of the Reglamento de Requisitos de los Sistemas y Programas Informáticos de Facturación (RRSIF), and it affects any Spanish company or freelancer that uses software to issue invoices, including SaaS that charge through payment gateways like Stripe.

The problem is that most SaaS founders assume that Stripe covers them. It doesn’t. Stripe Invoice is not a legal Spanish invoice. And while you build features, the clock is ticking.

#The real problem: three reasons why integrating Verifactu into an existing SaaS is a pain

#1. Modifying code in production involves real risk

Your collection flow already works. Every webhook, every retry logic, every proration management takes hours of accumulated work. Adding a billing integration on top of that system is adding complexity in production: new calls to external APIs, new points of failure, new statuses to manage.

A bug in the billing flow is not a minor bug. It can mean duplicate invoices, unsent invoices, or invoices with errors that the IRS considers violations.

#2. Exhaustive testing is unavoidable if you do it yourself

what happens when a customer cancels mid-cycle and you need an amendment invoice? When a payment fails on the first attempt but is collected on the second? When a customer has a credit applied that reduces the taxable base? When you change pricing and you have subscribers on the old plan?

Each of these edge cases requires test coverage. And Stripe’s casuistry, combined with Verifactu’s technical requirements, multiplies the scenarios.

#3. Maintenance is continuous, not ad hoc

Stripe updates its API. Verifactu technical requirements are refined. Tax regulations change. Each of these changes may require updates to your integration. If you’ve developed the logic in-house, that maintenance is yours forever.

#Why Stripe Invoice is not enough

This is the most common misunderstanding among SaaS founders. Stripe has an invoicing system, but it does not meet Spanish legal requirements:

• It does not generate CSF (Electronic Signature Code), which is mandatory in Verifactu
• Does not implement cryptographic chaining between consecutive invoices
• Does not generate the verifiable QR required by the IRS on each document
• Does not send the records to the AEAT systems in the required format
• It is not certified software under RRSIF

A Stripe Invoice is a collection document. A Verifactu-compliant Spanish invoice is a tax document with specific technical requirements. They are different things.

#The traditional options (and why they are a pain)

#Option A: Integrate a billing API manually

The classic technical route: you listen for Stripe webhooks (payment_intent.succeeded, invoice.payment_succeeded, customer.subscription.deleted…), validate the data, call a billing API, handle errors, resend if it fails, email the invoice.

We’re talking between 500 and 1,000 lines of code of integration, between 2 and 4 weeks of development, plus testing and more indefinite maintenance. And that’s assuming the first integration goes well.

#Option B: Delegate to a management company

Works for low volumes. From 50-100 transactions per month, the cost of a gestoria handling invoices manually ranges between 150 and 300 € per month, and most importantly: it doesn’t scale. When you have 500 Stripe payments a month, no one is going to do 500 invoices by hand.

#Option C: Develop your own Verifactu system

Some technical teams consider building their own certified solution. The real cost: between 10,000 and 20.000 € of development, plus certification, plus maintenance of the cryptographic modules. An investment that only makes sense if billing is your core product.

#The solution: Stripe Connect + BeeL without touching your codebase

BeeL connects to your Stripe account via Stripe Connect and automatically detects each payment. You don’t need to modify a single line of your code.

#How it works in practice

The complete flow looks like this:

Stripe (payment collected)
  → Stripe Connect (BeeL listens for events)
    → BeeL detects the type of payment (Payment Link, Subscription, Checkout)
      → Generates invoice with all Verifactu requirements
        → [Optional] Send to customer by email automatically

The steps from your side are five, and they are all done in the BeeL interface:

1. You create your BeeL account (5 minutes)
2. Connect your Stripe account via OAuth (Stripe Connect)
3. BeeL starts detecting payments in real time
4. Each payment generates a Verifactu invoice in compliance with Spanish regulations
5. Customer receives invoice by email (if activated)

#What you do NOT have to do

• ✗Modify your production code
• ✗Set up Stripe webhooks for billing
• ✗Implement CSF logic or cryptographic chaining
• ✗Do edge case testing (refunds, prorations, payment failures)
• ✗Maintain integration when Stripe updates its API
• ✗Worry about which version of the regulation is current

#What BeeL does automatically for you

• ✓Detects Payment Links, Subscriptions and Stripe Checkout
• ✓Generates invoices with CSF, QR and cryptographic chaining
• ✓Manages prorations, refunds and amendment invoices
• ✓Sends the invoice to the customer by email at the time of collection
• ✓Updates if Stripe changes its API or regulations evolve
• ✓Maintains the invoice register required by the IRS

#Advanced configuration for SaaS with specific needs

BeeL is not just plug-and-forget. You can configure:

• Filters by minimum amount: exclude payments below a threshold if you have trial transactions or micropayments
• Custom billing series: if you operate multiple product lines under the same Stripe and need separate series
• Multi-store: if you have multiple Stripe accounts or several different products
• Automatic sending to customer: enable or disable sending by email according to your flow

For more advanced use cases, the BeeL public API allows you to automate invoice management directly from your backend when you need full programmatic control.

#Real use cases

#Case 1: B2B SaaS with monthly subscriptions

A SaaS of tools for marketing teams has 200 active customers with Stripe subscriptions, priced between 49 and 299 € per month. Prior to BeeL, one team member spent 3-4 hours per month exporting payments from Stripe, creating the invoices in Word and sending them out one by one.

After connecting Stripe to BeeL via the subscriptions integration: 0 minutes per month. Each renewal generates your Verifactu invoice and is automatically sent to the customer’s email registered in Stripe.

#Case 2: Marketplace with Payment Links

A digital services platform uses Stripe Payment Links for its suppliers to charge customers directly. The volume is growing every month and manual invoice management was not scaling.

With BeeL, each completed Payment Link generates a corresponding invoice without human intervention. The marketplace can add 50 new suppliers without any additional operational burden on invoicing.

#Case 3: Online training platform (one-time + subscriptions)

A course platform has a combination of payments: lifetime access to specific courses (one-time payment via Stripe Checkout) and monthly memberships with full access (subscriptions). Previously, the team had to manually distinguish which invoices corresponded to which type of product.

BeeL automatically detects the type of payment by its nature in Stripe and applies the correct billing rules in each case. The transaction mix is handled without additional configuration.

#Verifactu: what you need to know as a technology company

If you want the full analysis of what Verifactu is and how it works, we have a dedicated article. The key points for a SaaS:

What is Verifactu: The invoicing control system of the Spanish Tax Agency. It obliges all software that issues invoices to comply with specific technical requirements: CSF generation, cryptographic chaining between consecutive invoices, verifiable QR and, depending on configuration, sending records to the AEAT.

Technical requirements that your invoicing software must meet:

• Generation of Electronic Signature Code (ESC) unique per invoice
• Cryptographic linkage between consecutive records (to ensure that no invoices have been deleted)
• QR verifiable by IRS on each document
• Specific file format for invoice registration

Key dates: Verifactu is mandatory from 1 January 2027 for companies and from 1 July 2027 for self-employed. If you want to see the full detail of dates and the context of the deferral, you have it in our article about the new Verifactu dates.

#Comparison: integrating manually vs using BeeL

#Frequently Asked Questions

#Conclusion: Avoiding it won’t make it fix itself

Verifactu is coming. It’s not a proposal, it’s a regulation published in the BOE. And the closer you get to the deadline, the less margin you have to make the right choice.

BeeL integration with Stripe is set up in less than 5 minutes. You don’t touch your code, you don’t configure webhooks, you don’t test. You connect your Stripe account and the invoices start generating themselves. Every hour you spend thinking about how to solve this internally is an hour you could have invested in your product.

#Related resources

• What is Verifactu and how does it work - complete guide to the regulation
• Verifactu postponed to 2027: new official dates - final dates and what changed
• BeeL integration with Stripe - technical documentation of integration
• Payment Links with Verifactu - configuration for Payment Links
• Stripe subscriptions with automatic billing - automatic renewals
• View BeeL Pricing - available plans