What it covers

A versioned REST surface covering the things businesses build most:

• Create and send invoices and payment requests from your own systems.
• Read and update your clients and vendors.
• Subscribe to signed webhooks so a paid invoice or a new bill can kick off your own code.
• Record payments and react when money comes through your processor.

The API will live at https://developers.wrenbase.com/api/v1.

Build a headless experience

The Wrenbase workspace is one way in, not the only way. The same engine that runs it is available over the API, so the invoicing and payments can run underneath your own product, with your own UI on top.

Some of what that makes possible:

• Your customers create and send invoices without leaving your product. Wrenbase handles the documents, delivery, and tracking in the background.
• Your ERP, CRM, or internal tools can raise invoices, check payment status, and reconcile, so nobody is copying data between tabs.
• Webhooks tell your code the moment an invoice is paid or a bill arrives, and you decide what happens next.

A button click in your app and an API call from your backend hit the same records and the same money engine, so nothing drifts out of sync.

Working today

The MCP server is already live, so if you want an AI assistant to drive invoicing right now, you can connect one without waiting for the REST API.

Early access

Can’t wait for the REST API? Email hello@wrenbase.com with your use case and we’ll find a way to unblock you.