Outvoicer MCP

An unofficial MCP server for preparing and creating invoice drafts in Outvoicer.

Purpose

I already use MCP servers, so connecting Outvoicer was a natural next step. Its public API makes it possible to prepare, create, and send invoices through conversation.

This project was created in collaboration with Martin Sookael, founder of Outvoicer.

I use OpenCode, but the server also works with compatible clients such as ChatGPT and Claude.

Scope

The current focus is limited to:

• Creating invoices

• Previewing invoices

• Sending invoices

Currently, it does not manage Outvoicer account data, integrations, or settings. These can be managed at outvoicer.com.

Authentication

Public lebo.agency endpoints use OAuth through oauth.lebo.agency.

The server validates Outvoicer credentials against the tenant selected by the URL before starting a session.

Security

• Public access is protected by OAuth.

• Credentials are tenant-specific and isolated between requests.

• Sessions are limited and automatically expire.

• Responses and telemetry exclude sensitive data.

Technology

• TypeScript provides static typing, while Bun runs the application and manages packages.

• Cloudflare Workers hosts the server.

• Hono handles HTTP requests, and the Model Context Protocol SDK provides MCP support.

• Zod validates data.

• Langfuse and OpenTelemetry provide tracing and observability.

About

This project is maintained by Kristjan Suursoho, who works with Outvoicer as a freelancer. It is an unofficial project and is not maintained or published by Outvoicer.

The Outvoicer API, internally known as Tetris, is available at api.outvoicer.com. OpenAPI documentation is available there.