Inference

Images

OpenRouter's Image API: a text prompt in, images out, never streamed. The request resolves to one size the model declares: an explicit size; else resolution keeps the sizes of that tier and aspect_ratio picks the first of them with that ratio; with neither, the model's first size. Only the parameters the model declares reach the provider. A provider may return fewer images than n, and you pay for the images returned: a model priced per image bills each image, one priced per token the tokens the provider reports. A high-quality image can take minutes, so allow a long client timeout. GET /api/v1/images/models lists the image models your key can call and the values each takes.

POST/api/v1/images

Your key

Request

curl -X POST https://api.llm.buzz/api/v1/images \
  -H "Authorization: Bearer $LLM_BUZZ_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "qwen/qwen-image-3",
  "prompt": "A honeycomb engraved on a copper plate",
  "aspect_ratio": "16:9"
}'

Response

{
  "created": 1792900000,
  "data": [
    {
      "b64_json": "iVBORw0...",
      "media_type": "image/png"
    }
  ],
  "usage": {
    "prompt_tokens": 0,
    "completion_tokens": 4175,
    "total_tokens": 4175,
    "cost": 0.03
  }
}

{
  "error": {
    "code": 400,
    "message": "qwen/qwen-image-3 serves aspect_ratio 1:1, 4:3, 3:4, 16:9, 9:16, 3:2, 2:3; resend with one of them.",
    "metadata": {
      "error_type": "invalid_request",
      "gateway_code": "invalid_parameter",
      "param": "aspect_ratio"
    }
  }
}

{
  "error": {
    "code": 401,
    "message": "A valid gateway Bearer key is required. Send the virtual key as 'Authorization: Bearer <key>'.",
    "metadata": {
      "error_type": "authentication",
      "gateway_code": "invalid_key"
    }
  }
}

{
  "error": {
    "code": 402,
    "message": "...",
    "metadata": {
      "error_type": "payment_required",
      "gateway_code": "insufficient_credits"
    }
  }
}

{
  "error": {
    "code": 404,
    "message": "The requested model does not exist or is not granted to this key. GET /api/v1/models lists the model aliases available to this key.",
    "metadata": {
      "error_type": "not_found",
      "gateway_code": "model_not_found",
      "param": "model"
    }
  }
}

{
  "error": {
    "code": 429,
    "message": "...",
    "metadata": {
      "error_type": "rate_limit_exceeded",
      "gateway_code": "unavailable_route"
    }
  }
}

Authorization

An inference key, as Authorization: Bearer KEY.

Keys and limits

Body application/json

modelstringrequired
An image model from GET /api/v1/images/models, such as qwen/qwen-image-3; a chat or embeddings model is a 400 on model. The :floor and :nitro suffixes work as on chat.
promptstringrequired
What to draw, 1 to 32,000 characters.
nintegerdefault 1
How many images, 1 to 10 and at most the model's most images per request.
sizestring
A size the model declares, WIDTHxHEIGHT or auto, or a resolution tier such as 1K or 2K, read as resolution.
aspect_ratiostring
A ratio the model declares, such as 16:9: the first declared size with that ratio.
resolutionstring
A tier the model declares, such as 1K or 2K.
qualitystring
A value the model declares; a model that declares none ignores the field.
backgroundstring
A value the model declares; a model that declares none ignores the field.
output_formatstring
A format the model declares; a model that declares none ignores the field.

pngjpegwebp
output_compressioninteger
0 to 100, forwarded only to a model that takes it.
seedinteger
Forwarded only to a model that takes it.
providerobject
Steers one request across the model's providers. With the OpenAI SDK, send it in extra_body. Every field accepts null. A name matches a provider's display name, its tag or the tag's first part, ignoring case: llm.buzz or llm-buzz names llm.buzz's own provider, and llm-buzz/eu only its capacity in the EU.
Show 7 child fields
- orderstring[]
  Try these providers first, in this order, then the others. At most 64 names.
- onlystring[]
  Use only these providers.
- ignorestring[]
  Never use these providers.
- allow_fallbacksboolean
  false stops moving to other providers.
- sortstring
  The order to try providers in. Ignored when order is set.
  
  pricethroughputlatencysmart
- zdrboolean
  true keeps the request on providers that declare 0 days of retention.
- data_collectionstring
  deny keeps the request on providers that declare no training and 0 days of retention.
  
  allowdeny
userstring
Your end user's label, recorded and never forwarded.

Response 200

The images, each as b64_json with the media_type its bytes show (PNG, JPEG or WebP), and usage, whose cost is in US dollars. The X-Generation-Id header names the call's generation record, GET /api/v1/generation.

Errors

400
Before any provider call: a field is missing or malformed, or names a size, ratio, tier or value the model does not declare, or n is above its most images. metadata.param names the field, and the message what to send. A chat or embeddings model, input_references, stream: true, output_format: "svg" and response_format: "url" are refused the same way.
401
No key, or the key is unknown, expired, revoked or disabled.
402
Your balance is spent and the model is not free, or the request could cost more than your balance.
404
No model has this name, or your key may not call it.
429
Providers are throttling, or the model is at capacity (unavailable_route): retry after Retry-After seconds. Or a free offer's allowance is used (free_allowance_exceeded): your organization's tokens, or your key's requests per minute. Choose a paid model, or for the per-minute limit retry after Retry-After seconds.

Every error code