Black Forest Labs

black-forest-labs/flux-2-pro/image-to-image

Image to Image

Black Forest Labs FLUX.2 Pro edits photos from written instructions with studio-grade realism, keeping people, products and lighting consistent. Combine up to 10 reference images for retouching, product placement and scene changes, with auto sizing or six presets, JPEG or PNG output and repeatable seeds.

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Usage-based · about $0.045 / request · $0.045 reserved per request

FLUX.2 Pro Image to Image example
Example — generated from this input

Change the view outside the studio window to a snowy winter afternoon with soft, cool daylight, and turn the unfired clay bowl on the wheel into a finished bowl with a glossy cobalt-blue glaze. Keep the woman, her pose, her clothing, the shelves and the rest of the studio exactly the same.

Pricing

Billed by actual usage; there is no fixed unit price.

Typically about $0.045 per request at default settings.

Each request temporarily reserves $0.045; you are charged for actual usage, usually within a minute: any unused amount is released and any usage above it is charged to your balance, even if that takes it below zero; while your balance is below zero, new requests are paused until a top-up covers it.

Failed generations are not charged.

API

Submit generation requests with this model ID.

POST/v1/model-tasks
black-forest-labs/flux-2-pro/image-to-image
Request body
{
  "model": "black-forest-labs/flux-2-pro/image-to-image",
  "input": {
    "prompt": "Change the view outside the studio window to a snowy winter afternoon with soft, cool daylight, and turn the unfired clay bowl on the wheel into a finished bowl with a glossy cobalt-blue glaze. Keep the woman, her pose, her clothing, the shelves and the rest of the studio exactly the same.",
    "image_size": "auto",
    "image_urls": [
      "https://pub-a7287c8d5de944d984e22a5bd3ab9bbe.r2.dev/uploads/capability-demo-7556a2722f351390f47790b1c1fc8a36.jpg"
    ],
    "output_format": "jpeg"
  }
}

Input schema

ParameterTypeRequirementDefault
image_urlsarrayRequired—
promptstringRequired—
image_sizeobject | stringOptionalauto
output_formatstringOptionaljpeg
seedintegerOptional—

Response

The API returns a result or a pollable asynchronous task. See the examples and Schema below for the response mode and result fields.

Asynchronous task
Submit response
HTTP 202
/v1/model-tasksapplication/json
{
  "id": "task_example",
  "model": "black-forest-labs/flux-2-pro/image-to-image",
  "status": "queued"
}
Status response
HTTP 200
/v1/model-tasks/{id}application/json
{
  "id": "task_example",
  "model": "black-forest-labs/flux-2-pro/image-to-image",
  "status": "completed",
  "output": {
    "images": [
      {
        "url": "https://api.musespan.com/v1/model-tasks/task_example/artifacts/0"
      }
    ]
  }
}
File download
HTTP 200
/v1/model-tasks/{id}/artifacts/{index}Generated image (e.g. image/png)

When the task completes, file URLs in output point to this endpoint, numbered from 0. Send the same API key (Authorization header) when downloading.

Error response
HTTP 400
/v1/model-tasksapplication/json
{
  "error": {
    "code": "invalid_input",
    "message": "The input does not match this model's input schema. Check the model's API documentation.",
    "type": "invalid_request_error"
  }
}

Code examples

Async submission returns a task ID. Poll until status is completed, then retrieve the generated content from the result. Get your API key in the console.

# Use a new directory for each new generation. Rerunning here continues this task.
set -eu
test -s model-task-id.txt || python3 -c "import uuid; print(uuid.uuid4())" > model-task-id.txt
REQUEST_ID=$(cat model-task-id.txt)
# Idempotent: resending the same bytes with the same ID never charges twice.
curl --fail-with-body --retry 3 --retry-connrefused --request POST 'https://api.musespan.com/v1/model-tasks' \
  --header "Authorization: Bearer $MUSESPAN_API_KEY" \
  --header "X-Request-Id: $REQUEST_ID" \
  --header "Content-Type: application/json" \
  --data '{"model":"black-forest-labs/flux-2-pro/image-to-image","input":{"prompt":"Change the view outside the studio window to a snowy winter afternoon with soft, cool daylight, and turn the unfired clay bowl on the wheel into a finished bowl with a glossy cobalt-blue glaze. Keep the woman, her pose, her clothing, the shelves and the rest of the studio exactly the same.","image_size":"auto","image_urls":["https://pub-a7287c8d5de944d984e22a5bd3ab9bbe.r2.dev/uploads/capability-demo-7556a2722f351390f47790b1c1fc8a36.jpg"],"output_format":"jpeg"}}'
# Poll every 5 seconds for up to 25 minutes until status is completed or failed.
# Still queued (with queue_position) 5 minutes after submission: failed with queue_timeout, not charged.
# No result 15 minutes after acceptance (or no confirmation 15 minutes after submission): failed with generation_timeout, not charged.
# Any failure is final: generate again in a new directory (a new X-Request-Id).
# A 404 means the POST did not arrive: rerun this script to resend it with the same ID.
curl --fail-with-body 'https://api.musespan.com/v1/model-tasks/'"$REQUEST_ID"'' --header "Authorization: Bearer $MUSESPAN_API_KEY"