Introduction

The arbitr API lets you create translation projects, upload source files, poll progress, download deliverables, and check credit balance from your own tools.

What you need

• An arbitr account
• An API key from Settings → API Keys

The key plain text is shown once. If you lose it, rotate it and use the new key.

Base URL

https://api.arbitr.ai

All routes are under /v1. Send the key on every request:

X-API-Key: abr_live_…

X-API-Version: 1 is optional.

A separate test mode (abr_test_…) runs on the same host. It checks auth and request shape only — it does not run the translation pipeline. See Test mode.

Typical flow

1. Create a project and upload files — POST /v1/projects

2. Poll status — GET /v1/projects/{id}

3. Download results — deliverables list, single file, or zip

Language codes are lowercase BCP-47 (en-us, ja-jp). Use the values from GET /v1/languages.

Coding agents

Use the guided setup to install the CLI, connect an API key, verify access, and add persistent arbitr guidance.

Next

1. Create an API key

2. Make your first call

3. Quickstart: submit → poll → download

4. CLI — official arbitr command line, if you would rather not assemble HTTP yourself

5. Agent setup — playbook for a coding agent to install the CLI and verify a key

6. Agent skill — persistent CLI rules for later sessions

7. MCP — hosted tools for a coding agent; same API key, no OAuth yet