blackforestlabs/flux-1-schnell/text-to-image

Fast, high-quality image generation with strong prompt following, vivid detail, and minimal steps for rapid creative iteration and scalable production.

1. Get started

Use RunComfy's API to run blackforestlabs/flux-1-schnell/text-to-image. For accepted inputs and outputs, see the model's schema.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/blackforestlabs/flux-1-schnell/text-to-image \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": "A playful gray tabby kitten leaping after falling autumn leaves in a sunlit garden, shallow depth of field, warm tones"
  }'

2. Authentication

Set the YOUR_API_TOKEN environment variable with your API key (manage keys in your Profile) and include it on every request as a Bearer token via the Authorization header: Authorization: Bearer $YOUR_API_TOKEN.

3. API reference

Submit a request

Submit an asynchronous generation job and immediately receive a request_id plus URLs to check status, fetch results, and cancel.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/models/blackforestlabs/flux-1-schnell/text-to-image \
  --header "Content-Type: application/json" \
  --header "Authorization: Bearer <token>" \
  --data '{
    "prompt": "A playful gray tabby kitten leaping after falling autumn leaves in a sunlit garden, shallow depth of field, warm tones"
  }'

Monitor request status

Fetch the current state for a request_id ("in_queue", "in_progress", "completed", or "cancelled").

curl --request GET \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/status \
  --header "Authorization: Bearer <token>"

Retrieve request results

Retrieve the final outputs and metadata for the given request_id; if the job is not complete, the response returns the current state so you can continue polling.

curl --request GET \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/result \
  --header "Authorization: Bearer <token>"

Cancel a request

Cancel a queued job by request_id, in-progress jobs cannot be cancelled.

curl --request POST \
  --url https://model-api.runcomfy.net/v1/requests/{request_id}/cancel \
  --header "Authorization: Bearer <token>"

4. File inputs

Hosted file (URL)

Provide a publicly reachable HTTPS URL. Ensure the host allows server‑side fetches (no login/cookies required) and isn't rate‑limited or blocking bots. Recommended limits: images ≤ 50 MB (~4K), videos ≤ 100 MB (~2–5 min @ 720p). Prefer stable or pre‑signed URLs for private assets.

5. Schema

Input schema

{
  "type": "object",
  "title": "Input",
  "required": [
    "prompt"
  ],
  "properties": {
    "prompt": {
      "title": "Prompt",
      "description": "",
      "type": "string",
      "maxLength": 2048,
      "default": "A playful gray tabby kitten leaping after falling autumn leaves in a sunlit garden, shallow depth of field, warm tones"
    },
    "steps": {
      "title": "Steps",
      "description": "The number of diffusion steps; higher values can improve quality but take longer.",
      "type": "integer",
      "maximum": 8,
      "minimum": 1,
      "default": 4
    }
  }
}

Output schema

{
  "output": {
    "type": "object",
    "properties": {
      "image": {
        "type": "string",
        "format": "uri",
        "description": "single image URL"
      },
      "video": {
        "type": "string",
        "format": "uri",
        "description": "single video URL"
      },
      "images": {
        "type": "array",
        "description": "multiple image URLs",
        "items": { "type": "string", "format": "uri" }
      },
      "videos": {
        "type": "array",
        "description": "multiple video URLs",
        "items": { "type": "string", "format": "uri" }
      }
    }
  }
}