HarnessRouter

What is HarnessRouter?

HarnessRouter is a managed backend service that runs AI agents for you. Instead of spending months building sandboxes, orchestration, retries, cost controls, and tool integration, you send one API request and get finished work back — code, files, videos, games, documents. It supports leading agents like Codex, Claude Code, and Hermes out of the box, and handles upgrades, fixes, and maintenance behind the scenes.

Who it's for

• Product builders – anyone who wants to ship agent-powered features (video generators, code assistants, document processors) without building an agent runtime from scratch
• Startups – teams that need to move fast and validate an AI feature with minimal infrastructure overhead, using a service trusted by Y Combinator–backed companies
• Enterprise teams – organizations (including top medical research institutions and healthcare companies) that require traceable, controlled agent execution with sandboxing and permission guardrails

Key features

One API, multiple leading agents

HarnessRouter exposes a single endpoint that routes your request to any supported harness — Codex, Claude Code, Hermes, and more coming soon. Swap the harness with one config line; your integration code and output schema never change. Your app gets the best agent for each task without rewriting anything.

Managed sandbox and orchestration

Every agent run gets its own sandbox, runtime, tool orchestration, file and artifact management, sessions, streaming, retries, timeouts, permissions, and cost controls. HarnessRouter handles all of that — you only send work in and get results out. No need to maintain your own infrastructure for these complex layers.

Full observability and control

Trace every task step-by-step from a detailed execution overview. See the event timeline — user messages, tool calls, file changes, final artifacts — all rendered in a clean interface. You can configure each harness's settings when needed, giving you transparency and fine-grained control over agent behavior.

What stands out

Bring the world's best AI agents into your app, with one API.

This is the core promise and the biggest differentiator. Instead of stitching together separate agent APIs, building your own orchestration layer, and dealing with sandboxing and session management, HarnessRouter collapses all of that into a single integration. The result: you can ship agent features in three steps — drop a configuration file into your coding agent, describe your idea, and add an API key. The product handles the rest, including ongoing maintenance that would otherwise drain your engineering time.

Worth checking out if…

You want to add agent-powered capabilities (code generation, video production, document creation, autonomous task execution) to your app without becoming an expert in agent infrastructure. HarnessRouter is especially useful for teams that value fast iteration, need to swap agent models easily, and require safe, auditable execution environments — all wrapped in a simple API.