Run a partner model synchronously by canonical model ID.

Bearer token authentication. Normally a Firebase or Cloud JWT. A 'comfyui-' prefixed API key is also accepted in this header: the prefix classifies the value as an API key and it is validated exactly as if it had been sent in X-API-Key.

Caller-generated key that makes retrying one logical call safe. A call that reached the caller with an answer is recorded against its key for 24 hours, and a retry carrying the same key is answered from that record instead of dispatching - and charging - the provider a second time, marked Idempotent-Replayed: true. Keys are scoped to the workspace your credential carries, or to your user when it carries none - so the keyspace is shared by every member of a workspace rather than private to one caller. Make a key unique across the whole workspace, not just within your own client: a second member who reuses a key string is answered from the first member's record, or refused 409 if the request differs. Because the scope follows the credential and not the person, a credential that carries no workspace at all scopes to your user id instead - so retrying one logical call under a different credential can land in a different namespace, where it is dispatched and charged again. Retry with the credential you started with. A keyed request with no authenticated caller is refused 401. The guarantee is a billing one: a key is charged at most once. It is not a promise that a key is dispatched at most once, and it does not make a lost call resumable. Some answers are recorded but not replayable for the full 24 hours, and the billing guarantee is the half that always holds: the key stays consumed - the retry never re-runs and never re-charges - but it is answered 409 invalid_input instead of being served the original body. That happens whenever Comfy does not hold a copy of the response it can still stand behind; a response past the replay size cap and a result addressed by an asset URL Comfy does not host are the two you are most likely to meet. The second is the one worth planning for, because it looks like an ordinary success: which models answer with a Comfy-hosted asset link, how long one stays valid, and what a result carries when an individual asset could not be copied are stated in one place, under Result assets in the API reference, and this paragraph does not restate them. On a model that returns its result on the original call, an answer still holding a partner's own asset link is replayed for a few minutes - which is where a dropped connection puts an SDK's automatic same-key re-send, and while the partner's link is certainly still alive - and refused after that rather than replayed dead. So a prompt retry of a partially re-hosted result behaves exactly like any other replay, and only a later one meets the 409. That short window is deliberately not offered on a model that submits and is polled, because there the partner may have minted the URL long before your call collected it and its remaining life is unknowable - and those models do not need it: a call cut off mid-generation keeps its key holding the generation, so the same-key retry collects the original result rather than a recorded copy of it. A response past the size cap has no window either and is refused from the start. The action on any of these 409 invalid_input refusals is the same: use a new key. Only an answer a provider actually produced is recorded, though. A refusal Router raises on its own before dispatching anything - not enabled for you yet (403), unknown model (404), not entitled to the model (403), a body the model's schema rejects or that names a different model than the path (422), a malformed request (400 invalid_input) - dispatched nothing and charged nothing, so it releases the key: re-send the same key once you are on the rollout ramp or have corrected the request and it runs for real, rather than replaying the refusal or colliding with it as a 409. That turns on whether a provider was reached, never on the status, so a 400 content_policy_violation - the partner's own answer to a call that ran, which some models meter - is recorded and replayed like any other answer. Releasing a refusal that dispatched nothing frees nothing chargeable, so it does not weaken the at-most-once billing guarantee above.

Lowercase provider segment of the canonical {provider}/{model} model ID - the partner whose model is being run. Lowercase provider segment of the canonical {provider}/{model} model ID - the partner whose model is being addressed. The invocation route's provider path parameter and a catalog entry's provider field both reference this one schema, which is what keeps the listed IDs and the accepted IDs from drifting apart.

Lowercase model segment of the canonical {provider}/{model} model ID - the model to run within that provider. Lowercase model segment of the canonical {provider}/{model} model ID - the model to run within that provider. Shared by the invocation route's model path parameter and a catalog entry's model field, for the same no-drift reason as RouterProviderSegment.

Selects an alternate provider to serve this model, instead of its current default. Omitting it runs native dispatch on the model's own default provider; default, comfy, and comfyui are aliases for that same native behavior and name no override, because Comfy Router is never itself a serving backend. The alternate providers Router can retarget a model onto are fal, wavespeed, runware, and higgsfield; which of them a given model supports is reported by GET /v2/models/{provider}/{model}. When an alternate provider is selected, the native request body is translated into that provider's real schema unless strict_mode=true; see strict_mode and fallback_provider. Its refusals are checked in a fixed order, and an earlier one answers whether or not a later one would. A value that is not a registered provider at all is refused 400 with error_type: invalid_input. Then a request whose body selects a multipart operation (an edit - for example gpt-image's image field) is refused 409, also with error_type: invalid_input, whose detail begins "this request's image selects the edit operation" - but only when the named provider's translator for this model cannot itself serve that operation; a leg whose translator does carry the media is not refused and proceeds normally, so this is a per-leg refusal rather than a blanket one. Then a request that has already resolved a bring-your-own-key credential for the provider in the path is refused 409, also with error_type: invalid_input, whose detail begins this request resolved a BYOK credential - see the 409 on this route, where that detail is the only thing separating this case, and the multipart case above, from the Idempotency-Key one. That BYOK check runs whether or not the named provider has a leg for this model. Then the named provider's own gate refuses 403 with error_type: not_enabled when that provider is not turned on for you, and 503 with error_type: service_unavailable when the gate cannot be evaluated - a flag-evaluation failure, or a missing or nil gate entry. Only past all of those is a real provider that does not serve this model refused 400 with error_type: invalid_input, the same answer as a value that is not a registered provider at all - both mean the model_provider value cannot serve this model, and that 400's detail is human-readable and not a contract, so read GET /v2/models/{provider}/{model} to learn which providers a model does support rather than parsing it; past that 400, this workspace's partner-provider policy for the named vendor is evaluated too and can refuse 403 or 503 of its own. Neither this parameter nor fallback_provider is available on a BYOK request, and the two are unavailable in different ways: the credential was resolved for the provider named in the path while every alternate leg dispatches on Comfy's own key, so an explicit model_provider is refused with that 409, and fallback_provider is inert rather than refused - no retry against an alternate provider is attempted and the first attempt's own failure is what the caller receives. The same split applies to a multipart body: only an explicit model_provider reaches the 409 above, and only for a leg whose translator cannot serve the operation, while the automatic on-failure retry fallback_provider controls is simply skipped (inert, not refused) for any multipart body. Router defines no provider_not_available or validation_error error_type: these conditions fold onto invalid_input. The error_type set can still grow, so treat any value you do not recognize as internal_error rather than switching exhaustively.

Only meaningful together with model_provider. false (the default): the request body must be this model's own native contract, translated to the alternate provider's real schema - any native field that cannot be expressed exactly is dropped and disclosed via the response's X-Comfy-Router-Dropped-Params header, never silently. true: the body must already be the alternate provider's own real schema, passed through unmodified in both directions - no translation, so X-Comfy-Router-Dropped-Params is never sent, and provider fallback is disabled for the call because a body shaped for one provider cannot be replayed against another (see fallback_provider).

Controls whether Router retries this call against another of the model's registered providers when the first attempt fails for a reason attributable to Router's own side or to the specific provider tried - never for a reason attributable to the request itself (an unretried failure is refused exactly as it always was). Omitted, or any value other than false, turns fallback on (the default) and Router scans the model's registered alternates in a fixed order and retries once against the first eligible one. false turns fallback off: a failure is refused, never retried. A successful fallback response carries the X-Comfy-Router-Fallback-Provider header, naming the provider that served it; a fallback attempt that itself also fails does not carry the header, and no case retries a generation that may already have been submitted to a provider. Fallback also turns itself off, regardless of this parameter, on a request that resolved a bring-your-own-key credential, on a request whose body selects a multipart operation, and under strict_mode=true - each binds the call to one specific provider and cannot be faithfully replayed against another: the alternate leg would dispatch on Comfy's own key rather than on the caller's credential, no alternate translator is guaranteed to carry the multipart media field, and a strict body is already shaped for one provider rather than for the native contract. Each of those is inert, not refused - no retry is attempted and the first attempt's own failure reaches the caller unchanged. Only an explicit model_provider is refused, and see that parameter for the 409s it answers with; note that fallback's multipart disable is unconditional, while model_provider's multipart 409 applies only to a leg whose translator cannot serve the operation.

Opt in to refusing a top-level request-body field this model's input schema does not declare, rather than accepting it; nested fields are not checked, and nothing is refused for a model whose schema allows undeclared fields or has no authored schema, or on a queued submit sent with strict_mode=true.