# HarnessRouter

> Updated 2026-09-21 · type: tool · category: integration-orchestration · status: active · rev 1

HarnessRouter gives your product one Apache-2.0 API across agent harnesses (Codex, Claude Code, Hermes), so you can switch harness without rewrites.

- Open source: yes (Apache-2.0)
- Self-hostable: yes
- Pricing model: freemium
- Best for: A builder shipping a product on top of a coding agent who does not want to hardcode a single harness, and wants to try a new one, or fall back to another, through one interface instead of rewriting the integration each time.
- Last verified: 2026-09-21

- **Canonical:** https://gtmstacker.com/registry/tool/harnessrouter/
- **Source:** [github · harnessrouter/harnessrouter](https://github.com/harnessrouter/harnessrouter)
- **Tags:** integration-orchestration, mcp-agents, agent-harness, self-hostable, byo-key
- **Repository:** https://github.com/harnessrouter/harnessrouter

## Is HarnessRouter open source?

Yes, HarnessRouter is open source under the Apache-2.0 license.

## How much does HarnessRouter cost?

HarnessRouter has a free tier plus paid plans. The open-source version can be self-hosted with no license cost; you pay only for your own infrastructure.

## Can I self-host HarnessRouter?

Yes, HarnessRouter can be self-hosted (the source is available under the Apache-2.0 license).

## Alternatives & related

- [Monid](https://gtmstacker.com/registry/tool/monid/)
- [Google AX](https://gtmstacker.com/registry/tool/google-ax/)


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Apache-2.0 abstraction layer, pitched as an OpenRouter for agent harnesses: one API your product calls to run a task, retrieve the result, and switch between coding-agent harnesses (Codex, Claude Code, Hermes and others) without re-implementing each integration. It handles persistent sessions, file handling and streaming behind that single interface. It is self-hostable via Docker with your own keys and infrastructure, and a managed cloud version exists separately.

## Provenance

- Apache-2.0, ~1.8k stars, ~486 commits, and the one-API-over-many-harnesses design independently WebFetch-verified on the repo 2026-09-21 (github.com/harnessrouter/harnessrouter).
- Surfaced via the 2026-09-21 viral-posts brief (a widely-followed engineer's "finally, an OpenRouter for agent harnesses", ~730 likes / ~92k views).
- Curated from the GTM Stacker signal registry (2026-09-21 pass); license independently verified 2026-09-21.

## Why it matters for a GTM stack

The harness, the thing that lets an agent read files, call tools and loop, is becoming the layer teams get locked into, the same way they once got locked into a single model. HarnessRouter does for harnesses what OpenRouter did for models: put one API in front of them so your product can run a task on Codex today and Claude Code tomorrow without a rewrite. For a builder shipping GTM tooling on top of an agent, that is the difference between betting the product on one vendor's harness and keeping the option open. The honest read: this only pays off if you genuinely switch or hedge, the hosted version is where the money is, and every abstraction layer is another dependency to trust. If you are building on agents and do not want to be married to one harness, it earns a look.