Intelligent routing

Use model: "/auto" when AnonRouter should choose an eligible model for the request. The values auto and anonrouter/auto are accepted aliases, and any model string containing a * glob (for example meta-llama/*) also triggers automatic selection over the matching routes.

For a goal-specific model ID that also works in apps with only a model field, see choose a router: Cheap, Fast, Coding, Uncensored, TEE, and Free.

This page covers choosing a model. To choose which provider serves a model, and how AnonRouter fails over between providers, see provider routing and failover.

{
  "model": "/auto",
  "messages": [
    {
      "role": "user",
      "content": "Review this distributed system design."
    }
  ],
  "routing": {
    "strategy": "balanced",
    "max_cost_usd": 0.02
  }
}

The ticket you issue must also be automatic. Request a ticket with the same /auto or glob model, then send the completion with the matching value.

The routing object

The optional routing object shapes the candidate set and the choice:

strategy controls quality and price, not privacy. cost prefers cheaper, lower-tier models, quality prefers the highest quality tier, and balanced sits between them and can step up for complex prompts.

{
  "model": "meta-llama/*",
  "messages": [
    {
      "role": "user",
      "content": "Analyze this TypeScript API."
    }
  ],
  "routing": {
    "exclude": ["*/*-guard"],
    "strategy": "cost"
  }
}

Exclusions always win, and allow/exclude patterns match against both the provider/model form and the bare model id.

Privacy is never widened

When privacy_classes is omitted, the eligible set defaults to the privacy-preserving tiers (private, tee, e2ee). Automatic routing never silently adds a weaker tier. To let /auto also consider Anonymous routes, you must ask for it explicitly:

{
  "model": "/auto",
  "messages": [{ "role": "user", "content": "Summarize this text." }],
  "routing": {
    "privacy_classes": ["anonymous", "private"]
  }
}

If no model satisfies the constraints, the request fails closed rather than downgrading to a route you did not allow.

A TEE privacy label alone does not make an ordinary OpenAI client verify attestation. See TEE verification and encrypted inference for the checks a verifying client performs and the provider-specific limits. E2EE requests are bound to their provider and do not fall back to another route.

Automatic selection respects context limits and output budgets. An explicit output cap is preserved; AnonRouter does not shorten or summarize the prompt to make it fit.

Model suffixes

Add a suffix to a model id to choose how its provider route is picked, without a provider object:

{
  "model": "deepseek/deepseek-v4.1-flash-1017:private",
  "messages": [{ "role": "user", "content": "Summarize this contract." }]
}

:private, :tee and :e2ee are guarantees. If the model has no route at that level, the request fails instead of using a weaker one.

A suffix never weakens your saved privacy settings. With a Private floor on your account or workspace, :cheapest picks the cheapest Private route. Without one, it picks the cheapest route at any privacy level you allow.

E2EE routes still need the encrypted client flow described in TEE verification and encrypted inference.

Use one suffix per model id. A second suffix, or any suffix not listed here or under free models below (for example :online or :thinking), makes the id unknown and the request fails with model_not_found.

Free models (:free)

:free is different from the suffixes above. It does not change how a model is routed. It names a separate free model, creator/model:free, which exists only where AnonRouter lists one; adding :free to a model without a free version returns model_not_found. A free model does not combine with another suffix (400 free_variant_id_invalid) and is never picked by /auto. Free models run on Anonymous routes and need the account opt-in. See free models for setup, limits and errors.

Response headers

Successful requests report the actual selection:

• x-anonrouter-selected-model is the chosen provider/model.
• x-anonrouter-routing is auto when a model was selected automatically, or exact when you named a single model.

The response body's model field is also rewritten to the selected model. Any classification the router computes to make the choice is used in memory and is not stored as durable usage metadata.

Saved routing preferences

An account can save default routing behavior that applies when a request does not override it. Preferences are managed with a session.

Preferences carry a privacy_level that maps to a default privacy set:

• open allows anonymous, private, tee, and e2ee.
• balanced allows private, tee, and e2ee.
• maximum allows only tee and e2ee.

A pool_mode of all, include, or exclude with model_patterns narrows the default candidate pool, and strategy sets the default quality tradeoff.

These are defaults for /auto only. A workspace can also set a privacy boundary (privacy_boundary) that applies to every request. /auto never goes below it: when the boundary is stricter than privacy_level, /auto uses the boundary, and an /auto selection below it is refused with 403 privacy_boundary_not_met.