# Estimate a run

POST https://fusara.ai/api/v3/run/estimate

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.

## Example request

```bash
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."
}'
```

## Parameters


## 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.

- `model` (string, required): Exact public model ID from model discovery. Keep any variant suffix, including slashes.
- `prompt` (string): 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_url` (string): 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

### 200

OK

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

```json
{
  "cost": {
    "unit": "common_fuz",
    "expected": "40.0000"
  }
}
```

#### Response body

- `cost` (object, required)
- `cost.unit` (string, required): Billing unit: common_fuz.
- `cost.expected` (string, required): Current total draft estimate as a decimal string. No funds are reserved and no run is created.

### 400

invalid_header: supply only one authentication header, Authorization: Bearer or X-API-Key. invalid_json or invalid_request: malformed request body. invalid_media_url, unsafe_media_url or remote_media_redirect_invalid: replace the invalid or restricted source URL. unsupported_media_link, unsupported_media_url, remote_media_folder_not_supported or remote_media_document_not_supported: use a direct link to a supported media file.

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 401

authentication_required: the API key is missing or invalid. Public methods allow omission, but reject invalid supplied credentials.

#### Response headers

- `WWW-Authenticate` (string, required): Bearer authentication challenge. Values: "Bearer".
- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 403

permission_denied: the account cannot access this resource. remote_media_access_required, remote_media_download_disabled or remote_media_challenge_required: the source blocks automated download; use a publicly downloadable file.

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 404

remote_media_not_found: the source file is missing or its link has expired; replace the URL. resource_not_found: the selected model or a referenced media/model asset is missing or inaccessible.

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 410

media_expired: a referenced input has expired. Replace it with available media or import the original file again. Repeating the expired reference cannot restore it.

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 413

request_too_large: reduce the JSON body to at most 1 MiB. remote_media_too_large: use a smaller source file within the media upload limit.

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 415

unsupported_media_type: send the body as application/json.

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 422

validation_error: correct the fields identified by error.errors[].pointer; unknown fields and query parameters are rejected. estimate_requires_authentication: supply a valid API key when estimating with media or LoRA inputs. Settings-only estimates need no key.

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 429

rate_limited (retryable: true): wait for the indicated delay, then retry. Use bounded backoff if no delay is supplied.

#### Response headers

- `Retry-After` (integer): When supplied, the minimum number of seconds to wait before retrying a transient failure. Preserve the original idempotency key and body when retrying a submission. Minimum: 1.
- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 500

internal_error: unexpected server failure. Contact support if the failure persists; inspect error.retryable before retrying automatically.

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 502

remote_media_provider_unavailable (retryable: true): the source could not be resolved, is temporarily unavailable or throttled the download. Retry after the indicated delay, or use bounded backoff when absent.

#### Response headers

- `Retry-After` (integer): When supplied, the minimum number of seconds to wait before retrying a transient failure. Preserve the original idempotency key and body when retrying a submission. Minimum: 1.
- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 503

remote_media_provider_not_configured (retryable: false): this source's import service is unavailable; use another supported source or contact support.

#### Response headers

- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.

### 504

remote_media_timeout (retryable: true): the source download timed out. Retry after the indicated delay, or use bounded backoff when absent.

#### Response headers

- `Retry-After` (integer): When supplied, the minimum number of seconds to wait before retrying a transient failure. Preserve the original idempotency key and body when retrying a submission. Minimum: 1.
- `X-Request-Id` (string, required): Support/trace identifier for this HTTP request.

#### Response body

- `error` (object, required)
- `error.code` (string, required): Machine-readable request error code.
- `error.message` (string, required): Human-readable explanation.
- `error.retryable` (boolean, required): Whether the failure is transient. For uncertain POST outcomes, preserve the original idempotency key and body.
- `error.errors` (object[]): Field errors when applicable. Omitted otherwise.
- `error.errors.pointer` (string, required): JSON Pointer to the invalid field, such as /images/0/url.
- `error.errors.code` (string, required): Machine-readable field error code.
- `error.errors.message` (string, required): How this field failed validation.