Routing keys

A routing key is the API key your apps and agents send on every /v1 request, and it carries the routing plan for those requests: an ordered list of lanes (a Codex subscription, a Claude Code bridge, or a saved provider API key), which the gateway works through until one serves the request. The key decides where the work happens. It starts with pllm_ and goes wherever OPENAI_API_KEY goes.

Why the key carries the routing

• Change providers without touching code. Your app sets OPENAI_API_KEY once. Every routing change after that happens in the dashboard and takes effect on the next request, with no deploy.
• Use what you already pay for. Put subscription capacity first and metered API keys behind it. The API key bills only when the subscription runs out of capacity.
• Keep serving through provider trouble. In fallback mode, when a lane is rate limited or down, the request moves to the next lane and your app still gets its answer.
• One key per app or client. Each key has its own budget and its own usage trail, so you can cap and attribute spend per client.

Example layouts

Codex with OpenAI fallback is the everyday setup:

1. Codex     your ChatGPT subscription; serves everything it can at $0 metered
2. OpenAI    gpt-4o-mini on your API key; catches requests when Codex is out of capacity

Claude Code bridge with Anthropic fallback is the same idea for Claude:

1. Bridge       Claude Code on a server you own, backed by your Claude subscription
2. Anthropic    your Anthropic API key as the safety net

Classifier routing picks the lane by task. You write the instructions (“code tasks go to Codex, everything else to mini”) and a small model applies them to each request:

1. Codex     code generation and review
2. OpenAI    gpt-5-mini for everything else

Create and manage keys under Routing keys in the dashboard, or through the API with an account token. The raw key is shown once at creation; you can regenerate it any time.

Routing modes

• Fallback (default): the first lane serves every request. If it hits a rate limit, an exhausted usage window, or an error, the request falls through to the next lane.
• Classifier: a small model reads each request and picks the lane, following instructions you write. Configure the classifier model and instructions on the key.

Budgets

Give a key a monthly budget in USD and it stops serving once metered spend reaches the cap. Subscription-backed lanes (Codex, bridge) bill at $0, so by default they don’t eat the budget; the dashboard tracks what they would have cost on the API instead.

The three key types

Key	Prefix	Where it works
Routing key	pllm_	Inference on /v1/*. Goes in OPENAI_API_KEY.
Account token	sk_ (read+write), rk_ (read-only)	Management API under /v1/organizations/* and the CLIs.
Bridge token	pllb_	Auth between ProxyLLM and your own bridge server.

Give production apps only routing keys. Give agents and outside tools a read-only rk_ account token if they just need stats (Authentication).