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REST API

Use the REST API as the direct HTTP interface for creating, reading, and updating workspace work from services, scripts, and CI.

Authentication

Use API Keys for trusted backend services, scripts, CI jobs, and other workspace-scoped automation.

Use OAuth Apps when an app needs user-approved access or needs actions tied to the signed-in member.

What the API covers

The REST API covers workspace data such as initiatives, bugs, tasks, comments, documents, files, members, teams, taxonomy, and connected workflow records. Use the API reference for operation names, request fields, response fields, and schemas.

Choose auth based on the job:

Auth typeUse it for
Workspace API keyBackend services, internal scripts, CI, sync jobs, and trusted workspace automation.
OAuth access tokenApps, MCP clients, and agent integrations that need user-approved workspace access and the signed-in member's identity.

Agent work uses OAuth user tokens and follows the lifecycle described in Agent Sessions. Use Build a Local Agent or Build a Cloud Agent for implementation flow, then use the API reference for exact calls.

Documents and files

Use the document operations when automation needs to list documents by title, type, status, linked task, creator, or updater, or fetch one document body.

For images and videos, request a signed upload URL, upload the file, then use the authenticated asset URL in task descriptions, comments, or documents. Operation names, request fields, and response fields are listed in the API reference under Files.

Limits and errors

REST API responses with bodies are JSON. Successful operations return 200, 201, or 204.

Failed requests return an error object with code and message. Use the API reference for endpoint-specific response codes and schemas.

If you receive 429, pause and retry after the delay in the message. Public API requests are limited per credential; the default is 200 requests per 15 minutes with a burst cap of 40 per minute. Avoid tight polling loops. Cache stable data and use Webhooks when a service needs to react to changes.


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Related Articles

API Keys

Create and manage workspace-scoped API keys for backend services, CI, and trusted automation.

JavaScript

JavaScript SDK

Automate One Horizon from Node.js and TypeScript with generated clients and types.

MCP

Let AI assistants read and act on One Horizon work context through tools.

OAuth Apps

Add Log in with One Horizon or Connect One Horizon to your app, then act with user-approved workspace access.

  • Authentication
  • What the API covers
  • Documents and files
  • Limits and errors
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