Changelog

Every change to the public contract — the API, the webhook events, the MCP tools, the error codes — newest first. A version is a date; send it as AlphaCount-Version to pin it. A breaking change only comes with a new version, and the previous one keeps working for at least 90 days after the new one is announced here.

2026-10-19Copy Anchor Link

The first published version of the contract. Nothing changed for existing integrations; what is new is that it is written down:

• An OpenAPI 3.1 document of every operation — summary, description, the scope its key needs, answer schemas, examples and the error codes it can return — at /openapi.json.
• The AlphaCount-Version header: optional on requests, present on every answer; an unknown version is refused with api_version_unknown.
• An error reference with every code, in English and German.
• Idempotency-Key on POST /invoices is documented as what it always was: required.

Operations at this version: customers, products, invoices (create, list, retrieve, PDF, send, cancel), contracts and usage, and revenue share (partners, agreements, attributions, revenue events, entries, statements).