Developers
Factuarea's invoicing API: REST, SDK and MCP.
Integrate invoicing, VeriFactu and payments through REST, SDK or MCP. Start with a test key and no sales approval.
- ✓ 10-day trial
- ✓ No card required
- ✓ Cancel anytime
Compatible integrations and formats
WhatsApp
One base address
https://api.factuarea.com/v1
Two ways to authenticate the REST API
Authorization: Bearer
The secret key, in the usual header.
X-API-Key
The same key, if your HTTP client won't let you set Authorization.
OAuth 2.1 + PKCE · MCP
OAuth is reserved for third-party connections to the MCP server. The REST API uses a key through Bearer or X-API-Key.
And a prefix that decides the environment
That is all. No test subdomain, no mode parameter, no separate API version to get going.
Build without starting from scratch
Choose how to connect your product
REST, SDK, webhooks or MCP. Four ways into the same invoicing platform, with sandbox and VeriFactu included.
What will not break under you
Four headers, four promises
They show up on every request or every response. If you only take four things away from this API, take these.
- Idempotency-KeyA retry still produces one invoice.
- Factuarea-VersionThe contract is pinned to a date.
- X-RateLimit-RemainingRemaining capacity returns on every response.
201 CreatedPOST /v1/invoices- Idempotency-KeyA retry still produces one invoice.
- Factuarea-VersionThe contract is pinned to a date.
- X-RateLimit-RemainingRemaining capacity returns on every response.
- Factuarea-SignatureEvery webhook arrives signed and verifiable.
Plus a request identifier on every response: that is the number you hand to support when something does not add up.
Two surfaces
Your code comes in over HTTP. Your agent, over MCP.
It is the same API behind both, with the same permissions and the same environment prefix. What changes is how you call it and how much work it saves you.
- 345 routes across 37 resources.
- Two official SDKs, for TypeScript and PHP.
- 391 tools published over the same API.
Published surface
An integration that fits your stack
The OpenAPI contract, SDKs and MCP server share the same API. These figures are checked against the published surface so you can assess scope and maintenance before integrating.
- API operations
- 413
- resources
- 37
- MCP tools
- 391
- documentation pages
- 797
Compatible technologies and clients
TypeScript
PHP
OpenAPI
Claude
ChatGPT
Cursor
Logos identify compatible technologies or clients; they do not imply a commercial relationship or endorsement.
Questions
What gets asked before the first line of code
No. You go into the dashboard, open the developer settings, create a key with the test prefix and whatever permissions you want, and you can call it. The quickstart in the documentation reaches a first issued invoice in five minutes.
The test key is two clicks away
No sales call, no demo and no card. Create it, copy it and issue the first invoice.