Pi coding agent extension that routes every request through OpenRouter's free model tier — no paid API key needed beyond your OpenRouter account.
1. Install
pi install npm:pi-freerouter2. Set your OpenRouter API key
export OPENROUTER_API_KEY=sk-or-...Free key at openrouter.ai/keys.
3. Start Pi and select FreeRouter
FreeRouter appears in the model picker as auto [free-router]. Select it when
you want requests routed through OpenRouter's free model tier. If
OPENROUTER_API_KEY is not set, Pi still starts normally; pi-freerouter shows
the key error only after you send a prompt with auto [free-router] selected.
OpenRouter exposes dozens of free models (models with a :free suffix). Each has its own rate limit — typically a few requests per minute per model. The trick is to spread load across all of them automatically.
Every time Pi sends a request, pi-freerouter doesn't pick one model and hope for the best. It picks the next 3 available models from its sorted list and fires all three requests simultaneously.
Request arrives
│
├── model A ──────────────────── first token ──▶ WINNER → stream to Pi
├── model B ───── (slower) → aborted
└── model C ─── (even slower) → aborted
Whichever model emits its first token wins. The other two are immediately cancelled. Pi sees a single clean stream — it has no idea a race happened.
Failed models are skipped for a short cooldown period and then return to the pool:
| Failure | Cooldown |
|---|---|
| Rate limit (429) or server error (5xx) | 90 s |
| No first token within 30 s | 15 s |
| Request rejected (400/422) | 90 s |
Batch 1: [model A, model B, model C] → all hit quota
Batch 2: [model D, model E, model F] → model D wins
↑ model A–C recover after 90s and rejoin the pool
Each model is tried at most once per request. Once a winner is streaming, a 30-second idle window per chunk ensures a stalled connection is aborted promptly rather than left open.
Free models are sorted so the lowest-latency inference providers are always tried first:
- Groq
- Cerebras
- Fireworks
- Together
- Mistral
- Everything else (sorted by context window ascending)
The list of available free models is fetched when you first send a prompt with
auto [free-router] selected, then refreshed every hour in the background.
- Pi coding agent v0.78+
- OpenRouter API key (free tier is sufficient)
auto [free-router]sends your prompt, conversation context, and enabled tool definitions to OpenRouter and the selected free model provider. Do not use it for secrets, credentials, private source code, or regulated data unless that external processing is acceptable for your use case.- Keep
OPENROUTER_API_KEYin your shell, password manager, or local secret store. Do not commit it to this repository or paste it into prompts. - For untrusted prompts or repositories, start Pi with
--no-toolsor a narrow--toolsallowlist so model-generated tool calls cannot access more than you intended.
MIT