Scribo API

Free, AI-native e-invoicing — over plain HTTP.

Contents

• What is Scribo?
• What is the Scribo API?
  • Demo
• Getting started
  • Quickstart
  • Setup & prerequisites
• Usage
  • How it works
  • Examples
• Compliance
• FAQ
• Resources
• License

What is Scribo?

Scribo is a free, conversational e-invoicing tool. Describe an invoice in plain language — "bill Acme GmbH €2,400 for May design work" — and it drafts a structured invoice for you to review, download and send directly.

Just ask your AI agent about Scribo: it ships as an MCP server, a CLI, and a Claude/Codex skill, alongside a public HTTP API and a web app. Free forever — no credit card. You just need a sender email.

Built by Causa Prima — Scribo is built by Causa Prima, a company building agentic AI for the CFO office. It's our first freely available skill — an early glimpse of what we're building.

What is the Scribo API?

The Scribo HTTP API is the public contract every Scribo surface is built on — the skill, MCP server, CLI, and web app all call it. POST an invoice payload to /api/v1/invoices and get back a compliant invoice (a PDF with the matching EN 16931 XML embedded) plus a durable download URL.

It's anonymous and rate-limited — no signup, no API key required (optional bearer tokens unlock higher quotas for partners). The canonical OpenAPI 3.1 spec lives at /api/v1/openapi.json.

This repo is the public landing page for the API. The canonical, always-current reference is at scribo.causaprima.ai/docs/api.

Getting started

Quickstart

Generate an invoice with a single POST — no key required. (First invoice for a sender email? Verify it first — see the verification step below.)

curl -sS https://scribo.causaprima.ai/api/v1/invoices \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "X-Email-Verification-Token: $TOKEN" \
  -d '{
    "sender": {
      "legal_name": "Example GmbH", "country_code": "DE",
      "address_line1": "Example Allee 1", "postcode": "10115", "city": "Berlin",
      "tax_id": "DE123456788", "contact_email": "billing@example.com"
    },
    "recipient": {
      "legal_name": "Acme GmbH", "country_code": "DE",
      "address_line1": "Hauptstrasse 1", "postcode": "10117", "city": "Berlin",
      "tax_id": "DE987654321", "contact_email": "ap@acme.example"
    },
    "line_items": [
      { "description": "Senior consulting, 3 days", "quantity": "3",
        "unit_code": "DAY", "unit_price": "1200.00", "tax_rate": "19",
        "tax_category_code": "S" }
    ],
    "currency": "EUR",
    "due_date": "2026-06-01"
  }'

Returns 201 with an InvoiceRecord, including a durable download_url:

{
  "invoice_id": "f0b3c1e2-...",
  "format": "zugferd_comfort",
  "download_url": "https://scribo.causaprima.ai/i/f0b3c1e2-.../download",
  "validator_summary": { "valid": true, "validator": "invopop", "errors": [] },
  "magic_link_sent": true
}

Fetch the file from download_url — it's durable and re-downloadable any time.

Setup & prerequisites

• Base URL (production): https://scribo.causaprima.ai
• Auth: none — the /api/v1/* API is anonymous. Send Authorization: Bearer <key> only if you have a partner key for elevated quotas.
• Verification (first invoice per sender): the first invoice for each sender email must prove address ownership, or POST /invoices returns 401 email_verification_required. Request a challenge (POST /api/v1/scribo/email-verifications with { "email": … } — Scribo emails a 6-character code), redeem it (POST …/{id}/redeem with { "code": … } → { verification_token }), then send the token as X-Email-Verification-Token. One token covers ~30 minutes of invoices for that sender.
• Format: JSON over HTTPS. Numeric fields (quantity, unit_price, tax_rate) are strings holding decimals — the API rejects floats, to preserve precision.
• Idempotency: send an Idempotency-Key header — same key + same payload returns the original invoice, so retries are safe.
• Spec: the canonical OpenAPI 3.1 document is at /api/v1/openapi.json — generate typed clients with openapi-typescript, oapi-codegen, or any OpenAPI 3.1 tool.

Usage

How it works

Eight endpoints under /api/v1/*:

Method	Path	Description
POST	/api/v1/invoices	Generate a compliant invoice; returns an InvoiceRecord with a durable download_url.
GET	/api/v1/invoices/{id}/download	Stream the invoice file bytes.
GET	/api/v1/jurisdictions	List supported jurisdictions and their formats.
GET	/api/v1/openapi.json	The canonical OpenAPI 3.1 document.
POST	/api/v1/scribo/email-verifications	Request a sender email-ownership challenge (uniform 202, anti-enumeration).
POST	/api/v1/scribo/email-verifications/{id}/redeem	Exchange the 6-character code for a verification_token.
GET	/api/v1/scribo/email-verifications/{id}	Challenge status snapshot (polling fallback).
GET	/api/v1/scribo/email-verifications/{id}/events	SSE stream of challenge events.

The output format is chosen by a deterministic priority chain (e.g. a recipient.leitweg_id selects German XRechnung); see jurisdictions. To re-download, use the download_url from the create response as-is — it's durable. (A metadata re-fetch at GET /api/v1/invoices/{id} is deferred in Phase 1 and currently returns 404.)

Errors share one envelope:

{ "error": { "code": "rate_limited", "message": "Rate limit exceeded", "details": {} } }

Rate limits (per source IP / sender tenant): 600 req/min and 200 invoices/hour per IP; 5 invoices/min and 50 per 24h per sender. 429 responses carry retry_after_seconds, reset_at, and limit_code. Full error reference: troubleshooting.

Examples

Check supported jurisdictions

curl -sS https://scribo.causaprima.ai/api/v1/jurisdictions | jq

German B2G XRechnung — add a leitweg_id to the recipient (auto-selects XRechnung) and a payment_means block (required by XRechnung BR-DE-1). The rest of the payload matches the Quickstart:

"recipient": {
  "legal_name": "Bundesamt für Beispiele", "country_code": "DE",
  "address_line1": "Wilhelmstr. 1", "postcode": "10117", "city": "Berlin",
  "leitweg_id": "991-12345-67"
},
"payment_means": {
  "type": "credit_transfer", "iban": "DE89370400440532013000", "account_name": "Acme GmbH"
}

payment_means also accepts US bank details — account_number + routing_number (plus optional bic / bank) instead of iban — rendered on US plain-PDF invoices. XRechnung specifically requires the IBAN.

Compliance

Scribo emits invoices conforming to EN 16931, the European e-invoicing standard, with the relevant national CIUS. Every EN 16931 output (ZUGFeRD, XRechnung) is validated against the Invopop-hosted validator at generate-time — output that fails the rule set never reaches the user. US plain PDFs carry no EN 16931 XML and are rendered directly.

Supported formats

Jurisdiction	Format	Status
Germany (B2B)	ZUGFeRD COMFORT (PDF/A-3 hybrid + CII XML)	✅ Live
Germany (B2G)	XRechnung (UBL / CII)	✅ Live
United States	Plain PDF (no XML, no e-invoice claim)	✅ Live
France	Factur-X EN 16931	🔜 Coming soon
Spain	Facturae	🔜 Coming soon
Belgium / NL / LU / AT	Peppol BIS 3.0 UBL	🔜 Coming soon

Disclaimer: Scribo generates and validates compliant invoice documents. It is not tax or legal advice — Scribo does not determine your tax obligations, VAT treatment, or filing requirements.

FAQ

Is Scribo really free?

Yes — free forever. No credit card, no subscription, no paywall before your first invoice. You just need a sender email.

Do I need an account or signup?

No signup form. On your first invoice, Scribo verifies the sender email — a 6-digit code (or one-click link) arrives at that address; one verification covers ~30 minutes of invoicing. The same email doubles as your magic-link login for re-downloads later.

Which countries and formats are supported?

Live today: Germany — ZUGFeRD (B2B) and XRechnung (B2G) — and the United States (plain PDF). Coming next: France (Factur-X), Spain (Facturae), and Belgium / NL / LU / AT (Peppol BIS 3.0).

What does "EN 16931-compliant" actually mean here?

Every EN 16931 output (ZUGFeRD, XRechnung) is validated against the EN 16931-1:2017 rule set (via the Invopop-hosted validator) before it's returned. Output that fails validation never reaches you. US plain PDFs carry no EN 16931 XML, so no schematron validation applies.

Is the US version compliant?

Yes. There is no US e-invoicing mandate, so Scribo produces a fully compliant plain PDF.

Does Scribo give tax or legal advice?

No. Scribo generates and validates compliant invoice documents. It does not determine your tax obligations, VAT treatment, or filing requirements.

How do AI agents / LLMs use Scribo?

Scribo is built to be operated by an agent. It ships as an MCP server, a CLI, and a Claude/Codex skill, plus a public HTTP API and a web app — all on the same backend. An agent can discover Scribo, create an invoice, and return the file on a user's behalf.

Who builds Scribo?

Causa Prima — a company building agentic AI for the CFO office. Operated by Causa Prima Germany GmbH, Munich.

Resources

• Web app — scribo.causaprima.ai
• Documentation — scribo.causaprima.ai/docs
• Compliance & trust — scribo.causaprima.ai/compliance
• Causa Prima — causaprima.ai

Other Scribo surfaces

• Skill (Claude / Codex) — scribo-skill · docs
• MCP server — scribo-mcp · docs
• CLI — scribo-cli · docs
• HTTP API — scribo-api-docs · docs
• Brand hub — scribo

License

Proprietary — UNLICENSED. © Causa Prima Germany GmbH. All rights reserved. Distributed for use against the public Scribo API; not open-source. See LICENSE.