Fusara
Runs
Markdown ↗

Estimate a run

POST/api/v3/run/estimate

Overview

Accepts the same flat fields as POST /run and returns cost.unit and cost.expected for the current draft using the same preview preparation and published pricing as Workspace. Missing prompts or inputs do not block a price that can be calculated from the current settings; a quote does not validate readiness to generate. Actual text is included for text-dependent pricing. Settings/text estimates need no API key; supplied media or LoRAs require a valid key to resolve accessible inputs. Anonymous resource requests return 422 estimate_requires_authentication without fetching URLs or looking up resources. Supplied invalid credentials are rejected. No Run, execution receipt, paid generation, budget reservation or webhook delivery is created. Available with zero balance and during submission maintenance. Authenticated URL media may be imported/inspected. webhook_url is syntax-validated only. POST /run validates the complete request and fixes its price at acceptance.

Available without an API key. Account-specific inputs may require authentication. Authentication →

curl 'https://fusara.ai/api/v3/run/estimate' \
  -H 'Content-Type: application/json' \
  --data-raw '{
  "model": "qwen-image21-create",
  "prompt": "A white ceramic lamp on a pale lavender background, soft studio light."
}'

The fields below describe the shared request. Required inputs and additional settings depend on your model. Choose a model in the playground →

Request body

Flat model-specific settings and named reference arrays. Discover exact supported fields, defaults and bounds in GET /api/v3/models/{model}: request_schema. Unknown fields are rejected; there are no input/parameters wrappers. Maximum body: 1 MiB.

modelstringrequired

Exact public model ID from model discovery. Keep any variant suffix, including slashes.

promptstring

Text instruction. Availability and whether it is required depend on the selected model's request_schema. Estimates can omit it when the price is determined by settings alone.

webhook_urlstring

Optional public HTTPS callback URL; no registration required. Receives the full Run JSON, ready to save without another GET. Signature verification is optional; without it, sender authenticity is unverified.

  • Format: uri
  • Maximum length: 2048

Responses

OK

Illustrative response. Prices, IDs and URLs come from your own request.

Example response
{
  "cost": {
    "unit": "common_fuz",
    "expected": "40.0000"
  }
}
costobjectrequired
Nested fields 2
unitstringrequired

Billing unit: common_fuz.

expectedstringrequired

Current total draft estimate as a decimal string. No funds are reserved and no run is created.

Response headers

X-Request-Idstringrequired

Support/trace identifier for this HTTP request.