---

name: endpoints description: Complete BFL API endpoint documentation

BFL API Endpoints

Complete reference for all BFL FLUX API endpoints.

Base URLs

Recommendation: Use the global endpoint (api.bfl.ai) unless you have specific regional requirements.

Authentication

All requests require the x-key header with your API key:

x-key: YOUR_API_KEY

FLUX.2 Text-to-Image and Image-to-Image Endpoints

FLUX.2 [klein] 4B

POST /v1/flux-2-klein-4b

Fastest generation, 4B parameters.

FLUX.2 [klein] 9B

POST /v1/flux-2-klein-9b

Fast generation with better quality, 9B parameters.

FLUX.2 [max]

POST /v1/flux-2-max

Highest quality, supports grounding search.

FLUX.2 [pro]

POST /v1/flux-2-pro

Production balanced quality and speed.

FLUX.2 [flex]

POST /v1/flux-2-flex

Typography optimized, adjustable steps/guidance.

FLUX.1 Endpoints

FLUX1.1 [pro]

POST /v1/flux-pro-1.1

Text-to-image generation.

FLUX.1 Kontext

POST /v1/flux-kontext

FLUX.1 Kontext Max

POST /v1/flux-kontext-max

FLUX.1 Fill

POST /v1/flux-fill

Inpainting and object removal - you can achieve inpainting and object removal with specific prompting style with FLUX.2 models for better performance.

Common Request Parameters

Text-to-Image (T2I)

Image-to-Image (I2I)

Important: All FLUX.2 models (klein, pro, max, flex) support image-to-image editing via the input_image parameter. FLUX.2 is recommended over FLUX.1 Kontext for editing.

Preferred: Use URLs directly - The API fetches URLs automatically, which is simpler and more convenient than downloading and encoding to base64. Both URL and base64 work, but URLs are recommended when available.

FLUX.2 [flex] Specific

Resolution Constraints

• Minimum: 64x64 pixels
• Maximum: 4MP total (width x height)
• Multiple of: 16 (both dimensions)

Common Resolutions

Example Requests

Basic T2I Request

curl -X POST "https://api.bfl.ai/v1/flux-2-pro" \
  -H "x-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "A serene mountain landscape at golden hour",
    "width": 1024,
    "height": 1024
  }'

Response

{
  "id": "gen_abc123xyz",
  "polling_url": "https://api.bfl.ai/v1/get_result?id=gen_abc123xyz"
}

T2I with All Options

curl -X POST "https://api.bfl.ai/v1/flux-2-max" \
  -H "x-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "Professional headshot of a business executive",
    "width": 1024,
    "height": 1280,
    "seed": 42,
    "safety_tolerance": 2,
    "output_format": "png",
    "webhook_url": "https://your-server.com/webhook",
    "webhook_secret": "your-secret-key"
  }'

I2I Request (FLUX.2 - Recommended)

Edit images using any FLUX.2 model by passing the source image URL directly:

curl -X POST "https://api.bfl.ai/v1/flux-2-klein-9b" \
  -H "x-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "Change the floor color to light blue",
    "input_image": "https://example.com/room-photo.jpg"
  }'

For higher quality edits, use FLUX.2 [pro] or [max]:

curl -X POST "https://api.bfl.ai/v1/flux-2-pro" \
  -H "x-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "Change the background to a beach sunset",
    "input_image": "https://example.com/portrait.jpg"
  }'

Multi-Reference I2I (FLUX.2)

curl -X POST "https://api.bfl.ai/v1/flux-2-max" \
  -H "x-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "Person from image 1 wearing outfit from image 2 in setting from image 3",
    "input_image": "https://example.com/person.jpg",
    "input_image_2": "https://example.com/outfit.jpg",
    "input_image_3": "https://example.com/location.jpg"
  }'

FLUX.2 [flex] with Custom Steps

curl -X POST "https://api.bfl.ai/v1/flux-2-flex" \
  -H "x-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "A poster with text \"SUMMER SALE\" in bold typography",
    "steps": 50,
    "guidance": 7.0
  }'

Polling Endpoint

Get Result

GET /v1/get_result?id={generation_id}

Response States

// Pending
{ "status": "Pending" }

// Ready
{
  "status": "Ready",
  "result": {
    "sample": "https://bfldeliveryprod.blob.core.windows.net/results/...",
    "prompt": "...",
    "seed": 1234567890
  }
}

// Error
{
  "status": "Error",
  "error": "Error description"
}

Error Responses