Model Guide

Flux Kontext Max

Model ID: flux-kontext-max

Vendor: Black Forest Labs (FLUX)Modalities: ImagePrice: $0.0400 /requestUpdated: 2026-05-02

Flux Kontext Max by Black Forest Labs (FLUX) is optimized for image generation/editing workflows. Contracts follow ToAPIs docs for production-ready API integration.

Open in Playground Docs

Model Overview

Quick Answer

Supports prompt-based text-to-image workflows for marketing and creative assets.
Supports reference-guided generation for stronger style consistency.
Stabilize parameters in this guide first, then move into production API.

Flux Kontext Max Model Features

Core Section

Core capabilities and practical engineering value

High-quality generation

Generate production-ready visual assets via a unified API.

Reference consistency

Use references to stabilize style and composition.

Parameter tuning

Tune ratio/count/sampling for quality and cost balance.

How to Use Flux Kontext Max API

Set Authorization: Bearer <YOUR_API_KEY>.
Call image generation endpoint with model, prompt, and size.
Optionally pass reference_images for stronger consistency.
Poll task status and download output URLs.

When to Use

When generating marketing, e-commerce, and social visual assets quickly.
When reference-guided consistency is required.

Runtime Behavior

Uses unified image generation endpoints with task-style responses.
Poll task status and fetch result URLs after completion.

Key Parameters

Parameter	Type	Required	Default	Range	Description
model	string	Yes	flux-kontext-max	-	Exact model identifier from ToAPIs.
prompt	string	Yes	-	-	Primary image instruction prompt.
size	string	No	1:1	-	Output aspect ratio, model-dependent.
n	integer	No	1	-	Number of generated images per request.
reference_images	file[]	No	-	-	Reference images for style consistency.

Common Errors

400 invalid_request_error

Trigger: Missing or invalid payload fields.

Fix: Validate model/prompt/size payload fields.

Retry: Retry only after payload fix.

401 authentication_error

Trigger: Missing or invalid API key.

Fix: Verify Authorization header and key scope.

Retry: Retry after authentication fix.

FAQ

What is Flux Kontext Max best for?

Best for high-frequency creative generation and reference-guided consistency workflows.

Image or video model error: invalid apitype: -1

This usually means the request was sent to the wrong endpoint. Image and video models typically do not use the chat endpoint. Instead, submit the documented HTTP task request and poll the task status endpoint for results. Check the actual request code, URL, and payload first.

An image or video task failed, but the user was still charged

Ask the user for the task log or screenshot first and check whether input or output token usage appears. If token accounting shows up, the request was likely sent through a chat endpoint instead of the proper media workflow. Image and video models usually run as async HTTP task APIs: submit the task first, then poll by task id according to the relevant docs.

Mode Notes

Text to Image with Flux Kontext Max

Generate images directly from prompt instructions.

Mode Parameters

modelpromptsizen

Best Scenarios

Product key visuals
Ad creatives
Concept art

Reference-guided Image with Flux Kontext Max

Use references to generate style-consistent outputs.