Sign in

API

Build anything on top of Truster

Invoicing without the busywork

Truster's B2B API removes every bit of friction from creating invoices: add your workers once, and from then on a whole invoice batch is one call — a hundred workers at a time if you like, expenses and mileage included. The API verifies tax cards straight from the source, returns finished PDFs, and webhooks confirm events to your system. Retries are safe with idempotency keys — a network blip never produces a duplicate invoice.

The documentation is public: interactive Swagger docs (api.truster.com/api/v1/docs) and an integration guide (api.truster.com/api/v1/guide), readable without signing in. The guide is machine-readable markdown — hand it to your favourite AI and ask for an integration, and it's done. Truster's core also speaks the Connect protocol (JSON, gRPC and gRPC-web from the same endpoints) if you're building deeper.

Live in a day, not weeks

  1. 01

    Ask for an API key

    API keys come from our support. The key authenticates with a Bearer header, and /auth/verify tells you instantly which company it's connected to.

  2. 02

    Open the docs

    The Swagger docs and integration guide are public: api.truster.com/api/v1/docs and /guide. No sign-in, no NDA.

  3. 03

    Let your AI integrate

    Give your AI (Claude, Cursor, Copilot…) the guide's address and ask it to connect your system to Truster — the guide is written so the AI does the integration for you.

  4. 04

    Test in Mock Mode

    Our sandbox validates every call and requires a real key, but writes nothing to production. When everything works, we switch production on.

The documentation is open

Browse the API in Swagger or read the integration guide — both without signing in.

API docsIntegration guide

Invoices & batches

Create a single invoice or a whole batch in one call — and fetch the finished PDFs straight from the API.

Workers

Add workers by personal details, share code or business ID — keyed to your own externalKey.

Webhooks

Events push to your system the moment an invoice goes out or a payment lands.

Tax cards & garnishments

Live tax cards verified straight from OmaVero before invoicing.

One call, one finished invoice

The API answers in JSON — and a webhook carries the event to your system.

Illustration: an API call creates an invoice — the request is sent, the server answers 200 OK and a webhook delivers the event to the caller's own system.

API services
68
Protocols
Connect · gRPC · JSON
Sandbox
Mock Mode
Accounting exports
Netvisor · Fortnox · Procountor · Visma

Verified on 22 July 2026

First integration in days

Ask our support for an API key, or book a demo and we'll walk the API through your use case.

Book a demoFor AI: MCP