Flux 1 Fill

POST/v1/run

Flux 1 Fill is BFL's intelligent image editing model. Transform, retouch, and reimagine existing images using text prompts - from background replacement to artistic style conversion.

Request body

Submit an async generation request. The model field selects the model; other fields are model-specific input parameters.

stringmodelrequired

Model identifier. Set to bfl/flux-1/fill.

Default: bfl/flux-1/fill

stringpromptrequired

The prompt to fill the masked part of the image.

stringimagerequired

The image URL to generate an image from. Needs to match the dimensions of the mask.

Optional<string>mask

The mask URL to inpaint the image. Needs to match the dimensions of the input image.

Optional<string>output_format

The format of the generated image.

Allowed values: jpeg, png

Default: jpeg

Optional<integer>seed

The same seed and the same prompt given to the same version of the model will output the same image every time.

Response Schema

The submit endpoint returns an accepted generation task. Poll the result endpoint with the returned id for terminal outputs or errors.

Optional<string>error

Error message if the task failed. Empty on success.

stringidrequired

Unique identifier for the generation task.

Optional<string>model

Model ID used for the prediction.

Optional<array>outputs

Array of generated content. Empty when status is not completed.

stringstatusrequired

Status of the task: pending, running, completed, failed, or timeout.

Allowed values: pending, running, completed, failed, timeout

Model capabilities

array<string>capability_tagsrequired

Capabilities declared by the model registry.

Default: image-to-image

stringexecution_moderequired

Execution mode declared by the model registry.

Default: async

# 1. Submit a generation request
curl -X POST https://api.sandbase.ai/v1/run \
  -H "Authorization: Bearer $SANDBASE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "bfl/flux-1/fill",
  "prompt": "A knight in shining armour holding a greatshield with \"EROUTER\" on it",
  "image": "https://static.sandbase.ai/examples/bfl/flux-1/fill/input_image_0.jpeg",
  "output_format": "jpeg"
}'

# 2. If the response is still running, poll the returned id
curl https://api.sandbase.ai/v1/run/run_abc123 \
  -H "Authorization: Bearer $SANDBASE_API_KEY"

Response202 Accepted

{
  "id": "run_abc123",
  "model": "bfl/flux-1/fill",
  "status": "running",
  "outputs": []
}