Founding customer offer

50,000 invoices (€500) free for your first month

Generate and validate XRechnung and ZUGFeRD invoices with the real API. No credit card, no commitment. Pick a plan when you're ready, or walk away.

Only 5 of 5 slots remaining

API key in seconds. First compliant invoice in under a minute.

50,000 invoices

Invoice operations (generate + validate)

€500

Capacity value at the base rate (€0.01/invoice)

30 days

Full access, then pick a plan or walk away

What you get

XRechnung generation
POST a canonical JSON invoice, get back standards-compliant CII or UBL XML.
XRechnung validation
Upload or send XML, get a structured validation report using KoSIT rules.
ZUGFeRD generation
Get a PDF/A-3 document with an embedded XML invoice, ready for German e-invoicing.
ZUGFeRD validation
Upload a ZUGFeRD PDF and get a structured validation result.

1
Claim your slot
Click "Claim your founding slot" to register. The promo code FOUNDING500 is applied automatically.
2
Get your API key
Your API key is provisioned instantly. Start generating and validating invoices immediately.
3
Build and evaluate
Use your 50,000 invoices over 30 days. When you're ready, pick a plan that fits your volume.

What happens after the 30 days?: Your founding credits expire. You keep your account and API key. Pick a paid plan (Starter, Plus, or Pro) to continue, or do nothing — there's no charge and no obligation.
Do I need a credit card?: No. The founding offer is completely free. You only enter payment details if you choose a paid plan after the 30 days.
What counts as an 'invoice'?: Each API call — generating or validating an XRechnung or ZUGFeRD document — counts as one operation. 50,000 operations covers a lot of evaluation, testing, and early production use.
Is my invoice data stored?: No. InvoiceSpec processes documents without persisting them after the request. Zero data retention.

50,000 invoices (€500) free for your first 30 days. No credit card required.