FLUX Kontext edits a real photo from one plain sentence — no masks, no layers, no selection tools. The same FLUX Kontext endpoint also generates images from scratch, so a single integration covers both jobs. Choose the pro tier for fast production work, or the max tier when typography and prompt adherence have to be exact.
Required · to replace words in an image, write: Replace 'old text' with 'new text'
Public HTTPS URLs only (no base64) · up to 4 images · leave empty for text-to-image
1:1, 4:3, 3:4, 16:9, 9:16, 3:2, 2:3, 21:9, 9:21 · does not change the price
png (default), jpeg or webp
Try one of these prompts
Credit-based — 1 credit = $0.001 USD. Pay only for completed generations.
One sample at the cheapest tier (1 image).
FLUX Kontext is Black Forest Labs' in-context image model, built for editing by instruction: describe the change and it applies it while leaving the rest of the frame intact. One reAPI endpoint covers both text-to-image and editing from up to 4 reference images, across nine aspect ratios with PNG, JPEG or WebP output, in two tiers — Pro for fast production work and Max for the strongest typography and detail. Every request is billed per image at its tier's rate.
Real-world workflows and production use cases you can build and ship with this model.
Point FLUX Kontext at one product shot and describe the variant you need — new backdrop, seasonal setting, different colourway. It edits in place instead of regenerating the scene, so the product keeps its shape and label while everything around it changes.
Open the playground
Write Replace 'SALE' with 'REBAJAS' and the sign keeps its typeface, paint texture and perspective. For teams shipping one creative into several markets, FLUX Kontext removes the round trip back to a designer.
Start from a single reference portrait and let FLUX Kontext carry that person through new scenes, outfits and weather. Identity holds across a chain of edits, which is what makes FLUX Kontext usable for storyboards, explainer sequences and character-led ad sets rather than one-off images.
No selection tool. No layer stack. No inpainting mask. You describe the change and FLUX Kontext applies it to the region that matters — an entire editing pipeline collapsed into one call.
Black Forest Labs builds FLUX Kontext around context awareness, and it shows most when you edit the same subject repeatedly. A face stays recognisable through a sequence of changes instead of drifting into a different person by the third pass.
The pro tier runs at roughly five to six seconds per image. Quick enough to put FLUX Kontext behind a user-facing editor, where people tweak a prompt and expect to see the result — not queue a job and come back later.
Both edit and generate images with commercial use in mind, but they are built for different operators. FLUX Kontext is an API you call from your own product; Firefly is a creative-suite tool a designer drives by hand. The rows below compare how each one behaves rather than which is better.
Comparison reflects publicly documented behavior at the time of writing. Vendors change capabilities and packaging frequently — verify against each vendor's current documentation before making a purchasing decision.
Sign up at reAPI and generate an API key from your dashboard. Signup credits let you try FLUX Kontext before you add any funds.
OpenPOST a prompt to the images endpoint with model set to flux-kontext-pro or flux-kontext-max. Add image_urls when you want an edit instead of a fresh generation.
OpenThe FLUX Kontext request returns a task id. Poll the tasks endpoint until the status is completed, then read the image URL from the output. Full request and response shapes are in the API docs.
Opencurl -X POST https://reapi.ai/api/v1/images/generations \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "flux-kontext-pro",
"prompt": "Replace the background with a rainy Tokyo street at night",
"image_urls": ["https://example.com/portrait.jpg"],
"size": "16:9"
}'Rejected synchronously with the failing field named. Check enum values, ranges, and URL fields — nothing is charged.
401 means a missing or invalid Bearer key; 402 means the reserve exceeds your balance. Manage keys and credits in the console.
Reference material and outputs pass automated moderation. Rejected tasks fail with a clear error and a full refund.
A task that reaches a failed state is never charged — the reserve refunds automatically. Keep the task id and retry when ready.
Common questions about this model.
Explore more models in the same category.
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Try it in the playground or grab an API key to integrate now.