Black Forest Labs

Flux Kontext pro

Image

Balanced speed and quality for in-context editing

from $0.03 / call Flux Kontext pro API reference →
Model health Insufficient data
curl -X POST https://runapi.ai/api/v1/flux_kontext/text_to_image \
  -H "Authorization: Bearer $RUNAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "flux-kontext-pro",
  "prompt": "Edit this product photo: change the background to a tropical beach while keeping the product exactly the same."
}'
https://runapi.ai 1 endpoint

2 versions available

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Estimated: $0.03 / image

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Specifications

Technical details

Provider Black Forest Labs
Model ID flux-kontext-pro
Modality Image
Task types Asynchronous
API endpoint /api/v1/flux_kontext/text_to_image
Billing unit call
Input parameters aspect_ratio, callback_url, enable_prompt_expansion, enable_translation, model, output_format, prompt, safety_tolerance, source_image_url, watermark
Aspect ratios 21:9, 16:9, 4:3, 1:1, 3:4, 9:16
Output format jpeg, png
Catalog status Operational
HOW IT WORKS

Use This Model in 3 Steps

  1. Get Your Key

    Sign up for free and create an API key for flux-kontext-pro from the dashboard.

  2. Send a Request

    POST to /api/v1/flux_kontext/text_to_image with the flux-kontext-pro model slug and your parameters.

  3. Get Results

    Poll the task or follow the callback to retrieve the completed flux-kontext-pro result.

What this model offers

Flexible parameters

Configure 8 documented parameters, including aspect_ratio, enable_prompt_expansion, enable_translation, output_format, prompt.

Endpoint coverage

Exposes 1 public endpoint(s): text_to_image.

Webhook delivery

Asynchronous tasks accept a callback URL for completion notifications.

Usage-based billing

Metered by call with no subscription requirement.

Flux Kontext pro Pricing

Endpoint
Resolution
Duration
Price
text_to_image
Not available
call
$0.03 / image
API REFERENCE

Endpoint Specification

Endpoint
POST /api/v1/flux_kontext/text_to_image
Model ID
flux-kontext-pro
Task Types
text_to_image
Max Duration
Unavailable
Resolutions
Unavailable
Aspect Ratios
21:9, 16:9, 4:3, 1:1, 3:4, 9:16
Output Format
JPEG, PNG
Avg Generation Time
Unavailable

Request parameters

prompt

Required string

Image description (English only).

watermark

Optional string

Watermark identifier.

aspect_ratio

Optional string

Output aspect ratio. Default: 16:9. (21:9, 16:9, 4:3, 1:1, 3:4, 9:16)

callback_url

Optional string

Webhook URL for async notifications.

output_format

Optional string

Output format. Default: jpeg. (jpeg, png)

safety_tolerance

Optional integer

Content safety threshold. 0-6 for generation, 0-2 for editing. Default: 2.

source_image_url

Optional string

Source image URL for editing mode.

enable_translation

Optional boolean

Auto-translate non-English prompts. Default: true.

enable_prompt_expansion

Optional boolean

Expand the prompt with more detail. Default: false.

USE CASES

Product photography

Auto-generate lifestyle product photos for e-commerce catalogs that lack studio photography.

Game & concept art

Rapidly concept environments and characters before committing to final art.

Editorial illustration

Generate unique cover art and illustrations for blog posts and articles at scale.

FAQ

Frequently asked questions about Flux Kontext pro

How do I select flux-kontext-pro?

Pass the model ID shown in the quickstart.

What's the rate limit on this variant?

Per-key rate limits scale with your usage tier. The pricing page shows current limits. If you need higher throughput, contact support to discuss tier upgrades.

Can I switch variants later?

Yes. Variant is a parameter in the request. Switch by changing the model ID — no code changes, no re-authentication, no separate billing setup. All variants share the same API key and request shape.

Does it stream?

Where streaming is available, RunAPI streams end-to-end. LLM models support token-level streaming. Media models use async task polling or webhook callbacks for result delivery.

Where do I report quality issues?

Open an issue on the public GitHub repo or email support at [email protected]. Include the task ID and model ID so the team can investigate the specific generation.

Do I need a separate provider account?

No. Your RunAPI API key is enough to access this variant and every other model in the catalog. You do not need accounts with the underlying provider.

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