Black Forest Labs' open-weights multimodal flow transformer for in-context image generation and editing, available for non-commercial use with character consistency and style transfer capabilities
Details
flux.1-kontext-dev
Providers & Pricing (2)
FLUX.1 Kontext [dev] is available from 2 providers, with per-image pricing starting at $0.025 through Replicate.
replicate/flux.1-kontext-dev
fal/flux.1-kontext-dev
FLUX.1 Kontext [dev] API OpenAI-compatible
Integrate FLUX.1 Kontext [dev] via the Lumenfall OpenAI-compatible API to perform advanced in-context image generation and precise image editing using Black Forest Labs' flow transformer architecture.
https://api.lumenfall.ai/openai/v1
flux.1-kontext-dev
Text to Image Generate
Create images from text descriptions
curl -X POST \ https://api.lumenfall.ai/openai/v1/images/generations \ -H "Authorization: Bearer $LUMENFALL_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "model": "flux.1-kontext-dev", "prompt": "A serene mountain landscape at sunset", "size": "1024x1024" }'# Response:# { "created": 1234567890, "data": [{ "url": "https://...", "revised_prompt": "..." }] }import OpenAI from 'openai';const client = new OpenAI({ apiKey: 'YOUR_API_KEY', baseURL: 'https://api.lumenfall.ai/openai/v1'});const response = await client.images.generate({ model: 'flux.1-kontext-dev', prompt: 'A serene mountain landscape at sunset', size: '1024x1024'});// { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }console.log(response.data[0].url);from openai import OpenAIclient = OpenAI( api_key="YOUR_API_KEY", base_url="https://api.lumenfall.ai/openai/v1")response = client.images.generate( model="flux.1-kontext-dev", prompt="A serene mountain landscape at sunset", size="1024x1024")# { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }print(response.data[0].url)Image Editing Edit
Transform existing images with text instructions
curl -X POST \ https://api.lumenfall.ai/openai/v1/images/edits \ -H "Authorization: Bearer $LUMENFALL_API_KEY" \ -F "model=flux.1-kontext-dev" \ -F "[email protected]" \ -F "prompt=Add a starry night sky to this image" \ -F "size=1024x1024"# Response:# { "created": 1234567890, "data": [{ "url": "https://...", "revised_prompt": "..." }] }import OpenAI from 'openai';import fs from 'fs';const client = new OpenAI({ apiKey: 'YOUR_API_KEY', baseURL: 'https://api.lumenfall.ai/openai/v1'});const response = await client.images.edit({ model: 'flux.1-kontext-dev', image: fs.createReadStream('source.png'), prompt: 'Add a starry night sky to this image', size: '1024x1024'});// { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }console.log(response.data[0].url);from openai import OpenAIclient = OpenAI( api_key="YOUR_API_KEY", base_url="https://api.lumenfall.ai/openai/v1")response = client.images.edit( model="flux.1-kontext-dev", image=open("source.png", "rb"), prompt="Add a starry night sky to this image", size="1024x1024")# { created: 1234567890, data: [{ url: "https://...", revised_prompt: "..." }] }print(response.data[0].url)Gallery
View all 3 imagesFLUX.1 Kontext [dev] FAQ
FLUX.1 Kontext [dev] starts at $0.025 per image through Lumenfall. Pricing varies by provider. Lumenfall does not add any markup to provider pricing.
You can use FLUX.1 Kontext [dev] through Lumenfall's OpenAI-compatible API. Send requests to the unified endpoint with model ID "flux.1-kontext-dev". Code examples are available in Python, JavaScript, and cURL.
FLUX.1 Kontext [dev] is available through Replicate and fal.ai on Lumenfall. Lumenfall automatically routes requests to the best available provider.
FLUX.1 Kontext [dev] supports images up to 2048x2048 resolution.
Overview
FLUX.1 Kontext [dev] is an open-weights multimodal flow transformer developed by Black Forest Labs, designed specifically for in-context image generation and editing. It extends the foundational FLUX.1 architecture to allow for complex image-to-image workflows, enabling users to maintain consistent characters or styles across different compositions. This model is intended for non-commercial development and research, offering a high-fidelity bridge between text prompts and visual reference inputs.
Strengths
- Character Consistency: The model excels at maintaining the identity and features of a specific subject across multiple generated frames by leveraging reference images as “context.”
- Zero-Shot Style Transfer: It can adapt the aesthetic, color palette, and texture of a target image onto a new prompt without requiring specific LoRA training or fine-tuning.
- Complex Attribute Mapping: It demonstrates high accuracy in following dense textual instructions while respecting the spatial constraints and structural information provided in the input image.
- Prompt Adherence: Like other models in the FLUX.1 family, it minimizes common artifacts in hand rendering and manages high-density text within images effectively.
Limitations
- Non-Commercial License: The [dev] version is released under a restrictive license that prohibits revenue-generating applications, making it unsuitable for production environments without further licensing.
- Hardware Intensity: Due to the flow transformer architecture and the multimodal input requirements, it demands significant VRAM and compute compared to standard latent diffusion models.
- Prompt Sensitivity: Achieving the perfect balance between the input image context and the text prompt can require iterative testing, as the model may occasionally over-index on the reference image at the expense of prompt instructions.
Technical Background
FLUX.1 Kontext [dev] is built on a multimodal flow transformer architecture, a departure from traditional U-Net-based diffusion models. This approach uses flow matching to improve training efficiency and sampling quality. By integrating text and image embeddings into a shared latent space, the model treats visual context as a primary input alongside textual tokens, allowing for more natural in-context learning during the generation process.
Best For
FLUX.1 Kontext [dev] is best suited for storyboarding, character design sheets, and stylistic exploration where visual continuity is required across a series of images. It is an excellent choice for developers experimenting with advanced image-editing pipelines or researchers studying multimodal integration in large-scale generative models. You can experiment with its in-context capabilities through the Lumenfall unified API and playground, which simplifies the integration of its multimodal inputs into your development workflow.
Try FLUX.1 Kontext [dev] in Playground
Generate images with custom prompts — no API key needed.