Flux 3 Edit

POST/v1/run

FLUX 3 by Black Forest Labs edits up to 10 reference images from a text instruction, with strong prompt adherence and typography at 512px to 4K resolution tiers.

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-3/edit.

Default: bfl/flux-3/edit

stringpromptrequired

The prompt to generate an image from.

array<string>imagesrequired

Reference image URLs or data URIs, in image 1 through image 10 order. Each must be at least 256 pixels per dimension and at most 4 megapixels. The first controls auto aspect ratio.

Optional<string>resolution

Output resolution tier. 4k can take several minutes.

Allowed values: 512sq, 768sq, 1k, 2k, 4k

Default: 1k

Optional<string>output_format

The format of the generated image.

Allowed values: jpeg, png

Default: jpeg

Optional<string>aspect_ratio

The aspect ratio of the generated image.

Allowed values: 21:9, 16:9, 3:2, 4:3, 5:4, 1:1, 4:5, 3:4, 2:3, 9:16

Response Schema

The submit endpoint returns a run response. If its status is pending or running, poll GET /v1/run/{id} with the returned opaque ID until it reaches a terminal state.

stringidrequired

Opaque SandBase run identifier. Use it exactly as returned; no prefix is guaranteed.

stringstatusrequired

Current public run status.

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

Optional<string>model

Public SandBase model name used for this run.

Optional<array<object>>outputs

Present only for completed runs. Each object is capability-specific; inspect the selected model schema for its fields.

Optional<object>error

Present only for failed or timeout runs. Contains a public error type and sanitized message.

Optional<string>error.type

Stable public error category.

Optional<string>error.message

Sanitized error message safe to show to clients.

Optional<object>usage

Usage details when available.

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-3/edit",
  "prompt": "A red fox leaping over a stream in a pine forest, low-angle wildlife photograph.",
  "images": [
    "https://storage.googleapis.com/falserverless/example_inputs/flux2_pro_edit_input.png"
  ],
  "output_format": "jpeg",
  "aspect_ratio": "21:9"
}'

# 2. If the response is still running, poll the returned id
curl https://api.sandbase.ai/v1/run/f3d2e8a1-7c4b-4a12-9d2e-123456789abc \
  -H "Authorization: Bearer $SANDBASE_API_KEY"

Response202 Accepted

{
  "id": "f3d2e8a1-7c4b-4a12-9d2e-123456789abc",
  "model": "bfl/flux-3/edit",
  "status": "running"
}