Imagen

Flux API for Developers

Last updated Sep 23, 2026 · By ModelsLab Engineering

The ModelsLab FLUX API runs FLUX.1 dev, FLUX.1 Kontext dev and FLUX.2 klein on our own GPUs at $0.0047 per image list price, and FLUX.2 dev at $0.02 per megapixel. At 100,000 images a month, FLUX.1 dev costs about $0.0015 per image on the $149 Open Source Unlimited plan. FLUX pro models from Black Forest Labs run on the same key, billed per image. Prices checked September 23, 2026.

Get Your Flux API Key API Documentation

What is the ModelsLab Flux API?

FLUX.1 Image Generation, One REST Endpoint

The ModelsLab Flux API gives developers FLUX models through a single REST endpoint. You pass a model_id and a prompt to /api/v7/images/text-to-image and receive hosted image URLs in JSON. FLUX.1 dev, FLUX.1 Kontext dev, FLUX.2 klein 9B and FLUX.2 dev run on ModelsLab GPUs; FLUX1.1 pro, Kontext pro, FLUX.2 pro and FLUX.2 max are served by Black Forest Labs through the same key.

FLUX, from Black Forest Labs, is a rectified-flow transformer known for sharp detail, strong prompt adherence and legible in-image text. On one key you can draft with FLUX.2 klein, produce with FLUX.1 dev or FLUX.2 dev, edit with Kontext, and send the final render to a pro model with a one-line change.

ModelsLab manages GPU allocation, model loading and auto-scaling, so there is no worker image for you to build or keep warm. The same API key also covers 10,000+ other image, video, audio, and LLM models when your product grows beyond FLUX.

What You Can Build with the Flux API

The Flux API supports the full range of FLUX image workflows through one key:

Text-to-Image — Generate images from natural-language prompts with FLUX.1 dev, FLUX.2 klein, FLUX.2 dev or the pro models, up to 1024×1024 per request
Image Editing — Apply instruction-based edits to an existing image with FLUX.1 Kontext while preserving the rest of the scene
LoRA Styling — Attach FLUX LoRAs to steer style, or train and deploy your own for branded and subject-specific pipelines
Batch Generation — Request multiple samples per call for A/B testing and variation exploration
Async + Webhooks — Fire-and-forget generation with webhook callbacks for high-volume pipelines

Trusted by

1B+

Images Processed Monthly

500K+

Active Developers

5K+

Discord Community Members

300+

Available AI APIs

FLUX Models on the API

One endpoint, switched by model_id. Self-hosted models draw their list price from your plan and are included in Open Source Unlimited; BFL-hosted pro models bill per image on every plan.

Variant	Best for	Hosted by	ModelsLab price
flux	FLUX.1 dev: production images with strong prompt adherence	ModelsLab	$0.0047/image
flux-kontext-dev	FLUX.1 Kontext dev: instruction-based editing of a reference image	ModelsLab	$0.0047/image
flux-klein	FLUX.2 klein 9B: fast drafts and high-volume generation	ModelsLab	$0.0047/image
flux-2-dev	FLUX.2 dev: newer open-weight model, text-to-image and editing	ModelsLab	$0.02/megapixel
flux-pro-1.1	FLUX1.1 pro: highest fidelity for hero assets	Black Forest Labs	$0.06/image
flux-kontext-pro	FLUX.1 Kontext pro: premium instruction-based editing	Black Forest Labs	$0.048/image
flux-2-pro	FLUX.2 pro: premium FLUX.2 generation and editing	Black Forest Labs	$0.054/image

FLUX API Pricing by Provider

Price per 1024x1024 image, read on each provider's own page on September 23, 2026. A dash means the provider does not list the model, or we did not verify a price.

FLUX model	ModelsLab	fal.ai	Replicate	Together AI	Black Forest Labs
FLUX.1 [schnell]	—	$0.003	$0.003	—	—
FLUX.1 [dev]	$0.0047 (self-hosted)	$0.025	$0.025	—	—
FLUX.1 Kontext [dev]	$0.0047 (self-hosted)	—	—	—	—
FLUX.2 [klein] 9B	$0.0047 (self-hosted)	—	—	—	from $0.015
FLUX.2 [dev]	$0.021 (self-hosted, $0.02/MP)	—	—	$0.0154	—
FLUX1.1 [pro]	$0.06 (BFL-hosted)	$0.04	$0.04	$0.04	$0.04
FLUX1.1 [pro] Ultra	$0.08 (BFL-hosted)	—	—	—	$0.06
FLUX.1 Kontext [pro]	$0.048 (BFL-hosted)	$0.04	$0.04	$0.04	$0.04
FLUX.2 [pro]	$0.054 (BFL-hosted)	—	—	$0.03	from $0.03
FLUX.2 [max]	$0.24 (BFL-hosted)	—	—	—	from $0.07

Per-megapixel prices (fal, Together, FLUX.2 on BFL) are shown at one megapixel. ModelsLab list prices are what one call draws from a plan's monthly allowance; self-hosted models are also included in Open Source Unlimited. BFL-hosted models on ModelsLab are billed per image and are not part of any unlimited allowance.

Cheapest FLUX API for Each Variant

The lowest verified price per image, and where to buy it. Sometimes that is not us.

Variant	Cheapest verified	Where
FLUX.1 [schnell]	$0.003	fal.ai or Replicate (no first-party schnell endpoint on ModelsLab)
FLUX.1 [dev]	$0.0047, or ~$0.0015 at 100k/month	ModelsLab Standard or Open Source Unlimited
FLUX.1 Kontext [dev]	$0.0047, or included in $149/month	ModelsLab
FLUX.2 [klein] 9B	$0.0047, or included in $149/month	ModelsLab
FLUX.2 [dev]	$0.0154	Together AI; ModelsLab Open Source Unlimited above ~9,700 images/month
FLUX1.1 [pro], Kontext [pro]	$0.04	BFL, fal.ai, Replicate or Together AI
FLUX.2 [pro]	$0.03	BFL or Together AI

FLUX.1 dev Cost per Image on Each Plan

Effective price = plan price divided by the images you actually make.

ModelsLab plan	Price / month	Images / month	FLUX.1 dev per image
Basic	$21	3,250 calls	$0.0065
Standard	$47	10,000 calls	$0.0047
Open Source Unlimited	$149	10,000	$0.0149
Open Source Unlimited	$149	100,000	$0.0015
Open Source Unlimited	$149	1,000,000	$0.00015

Plan prices and call limits from the live plans table, 2026-09-23. Open Source Unlimited covers the self-hosted FLUX models with up to 15 generations in parallel.

FLUX price sources

Every competitor price above, with the date we read it.

fal.ai FLUX.1 [schnell] — $0.003/MP, read 2026-09-23
fal.ai FLUX.1 [dev] — $0.025/MP, read 2026-09-23
fal.ai FLUX1.1 [pro] — $0.04/MP, read 2026-09-23
fal.ai Kontext [pro] — $0.04/image, read 2026-09-23
Replicate flux-schnell — $3 per 1,000 images, read 2026-09-23
Replicate flux-dev — $0.025/image, read 2026-09-23
Replicate flux-1.1-pro — $0.04/image, read 2026-09-23
Replicate flux-kontext-pro — $0.04/image, read 2026-09-23
Together AI pricing — FLUX.2 dev $0.0154, FLUX.2 pro $0.03, FLUX1.1 pro and Kontext pro $0.04/MP, read 2026-09-23
Black Forest Labs API pricing — 1 credit = $0.01, read 2026-09-23

Flux API Quick Start

Generate a FLUX image in seconds with a single REST call — cURL, Python, or JavaScript.

Generate a FLUX image with cURL

curl

1curl -X POST "https://modelslab.com/api/v7/images/text-to-image" \
2  -H "Content-Type: application/json" \
3  -d '{
4    "key": "YOUR_API_KEY",
5    "model_id": "flux",
6    "prompt": "a neon-lit ramen bar in the rain, cinematic, 35mm",
7    "width": 1024,
8    "height": 1024,
9    "samples": 1,
10    "num_inference_steps": 4
11  }'

Generate with Python

Python

1import requests
2
3url = "https://modelslab.com/api/v7/images/text-to-image"
4payload = {
5    "key": "YOUR_API_KEY",
6    "model_id": "flux",
7    "prompt": "product photo of a matte black watch on concrete, studio lighting",
8    "negative_prompt": "blurry, low quality",
9    "width": 1024,
10    "height": 1024,
11    "samples": 2,
12    "num_inference_steps": 28,
13    "guidance_scale": 3.5
14}
15
16response = requests.post(url, json=payload)
17data = response.json()
18
19# data["output"] is a list of generated FLUX image URLs
20for i, image_url in enumerate(data["output"]):
21    print(f"Image {i+1}: {image_url}")

Edit an image with FLUX.1 Kontext (JavaScript)

JavaScript

1const response = await fetch('https://modelslab.com/api/v7/images/image-to-image', {
2  method: 'POST',
3  headers: { 'Content-Type': 'application/json' },
4  body: JSON.stringify({
5    key: 'YOUR_API_KEY',
6    model_id: 'flux-kontext-dev',
7    init_image: 'https://example.com/room.jpg',
8    prompt: 'change the sofa to emerald green velvet',
9    samples: 1
10  })
11});
12
13const data = await response.json();
14// data.output = array of edited image URLs
15data.output.forEach((url, i) => console.log(`Result ${i + 1}: ${url}`));

One Flux API, Every Variant Plus LoRAs

Text-to-image, image editing with Kontext, and custom LoRA fine-tunes — all behind a single FLUX endpoint and one API key.

Open and Pro FLUX Models

FLUX.1 dev, Kontext dev, FLUX.2 klein and FLUX.2 dev run on ModelsLab GPUs; the pro models come from Black Forest Labs. All use the same text-to-image and image-to-image endpoints, so switching is a model_id change.

FLUX LoRA Fine-Tuning

Attach existing FLUX LoRAs to steer style, or train and deploy your own. Custom LoRAs run through the standard endpoint by referencing them in the request — ideal for consistent brand or character styling.

Kontext Image Editing

FLUX.1 Kontext takes an input image plus an instruction prompt and applies the edit while preserving the rest of the scene. Product recolors, background swaps, and targeted changes all run through the API.

Predictable Plan Pricing

Self-hosted FLUX models draw their list price from a monthly plan, and the $149/month Open Source Unlimited plan removes the per-image charge on them entirely. Pro models bill per image, as listed in the pricing table.

Everything developers need to ship FLUX-powered image features in production.

Get Started

FLUX API Provider Comparison

How ModelsLab compares to other ways to access FLUX.1 models.

Feature	ModelsLab	fal.ai	Replicate	Black Forest Labs
FLUX models	FLUX.1 dev, Kontext dev, FLUX.2 klein and dev; pro via BFL	Schnell, Dev, Pro	Schnell, Dev, Pro	Pro, Ultra (official)
Other models on same key	10,000+	~50	Thousands (self-serve)	FLUX only
FLUX LoRA support	Attach + train	Attach	Attach + train	No
Image editing (Kontext)	Yes	Yes	Yes	Yes
Worker to build or keep warm	None, managed	Occasional	Frequent	None
Price model	$0.0047 list (self-hosted); plan or unlimited	Per-megapixel, varies by variant	Per-second + per-image	Per-image by tier
Unlimited plan	$149/mo	No	No	No

Feature comparison reviewed September 2026. For prices, use the dated table above.

Related image API guides

Image Generation API

Full catalog: FLUX, SDXL, SD 3.5, and 10,000+ models through one endpoint.

Stable Diffusion API

SDXL, SD 3.5, ControlNet, and LoRA via the same REST API and key.

Cheapest AI Image API

Image API prices beyond FLUX, compared across providers.

fal.ai pricing

What fal.ai bills at 10k, 100k and 1M images a month.

Replicate pricing

Per-second GPU billing, per-image FLUX prices and idle time.

How to Use the Flux API

Generate your first FLUX image in under 5 minutes.

STEP 01

Step 1: Get Your API Key

Create a ModelsLab account, subscribe to a plan (from $21/month), and generate your API key from the dashboard. Every plan can call every FLUX model on this page.

STEP 02

Step 2: Pick a Variant and Prompt

Send a POST request to /api/v7/images/text-to-image with model_id set to flux, flux-klein, flux-2-dev or flux-pro-1.1, plus your prompt and generation parameters like width, height, and steps.

STEP 03

Step 3: Get Your Images

Receive hosted image URLs in the JSON response, or a request id to fetch when the job queues. Use flux-kontext-dev with an init_image to edit images instead of generating from scratch.

Start Generating with Flux

Flux API Pricing

Self-hosted FLUX models (FLUX.1 dev, Kontext dev, FLUX.2 klein) list at $0.0047 per image and FLUX.2 dev at $0.02 per megapixel, drawn from your plan: Basic is $21/month for 3,250 calls and Standard is $47/month for 10,000. The $149/month Open Source Unlimited plan has no per-image charge on them, which is about $0.0015 per image at 100,000 images a month.

Pro models are a different story. FLUX1.1 pro costs $0.06 and Kontext pro $0.048 per image on ModelsLab, above the $0.04 that Black Forest Labs, fal.ai and Replicate charge direct (checked September 23, 2026). If you only need a pro model, buy it direct; use ModelsLab for the open-weight FLUX models at volume. Dedicated enterprise endpoints start at $249/month.

API Response Format

The Flux API returns a consistent JSON response. Generated images come back as publicly accessible URLs (available for 24 hours) or as base64 data for direct embedding. Synchronous requests return images in the response; for longer or batched jobs, use asynchronous mode and poll the fetch endpoint with the returned request_id, or register a webhook to receive completions.

Integration and SDKs

ModelsLab provides SDKs and integration paths for the Flux API across popular stacks:

Python SDK — pip install modelslab — full endpoint coverage with async support
JavaScript/TypeScript — npm install modelslab — works in Node.js, Deno, and the browser
REST API — standard HTTP endpoints usable from any language (cURL, Go, Ruby, PHP, Java)
Webhook callbacks — receive FLUX completion notifications for async pipelines
Documentation — per-parameter guides and examples at docs.modelslab.com

Why ModelsLab for the Flux API?

Key advantages that set us apart

FLUX.1 dev, Kontext dev, FLUX.2 klein and FLUX.2 dev on one endpoint

$0.0047 per image list price on self-hosted FLUX models

$149/mo unlimited plan for high-volume FLUX generation

Attach FLUX LoRAs or train and deploy your own

Kontext image editing through the same API key

No GPU worker to build or keep warm

FLUX pro models from Black Forest Labs on the same key

Async fetch and webhook support for queued jobs

10,000+ other image, video, audio, and LLM models on the same key

Plans start at $21/month (Basic, 3,250 API calls)

Our Popular Use Cases

What developers build with the Flux API:

Embed FLUX text-to-image and Kontext editing directly into design apps, letting users generate and refine high-fidelity visuals on demand.

Flux API FAQ

Your Data is Secure: GDPR Compliant AI Services

ModelsLab GDPR Compliance Certification Badge

GDPR Compliant

AI Image API Pricing: Plans From $21/Month

ModelsLab offers subscription plans from $21/month (Basic) and $47/month (Standard, 10,000 API calls, $0.0047 per image) to $149/month (Open Source Unlimited, no limit on self-hosted models). All plans include access to Flux, SDXL, Stable Diffusion 3, and 10,000+ community models. Choose a paid plan, cancel anytime, 100% refund policy.

Coming Soon

We are making some changes to our pricing, please check back later.

Get Expert Support in Seconds

We're Here to Help.

Want to know more? You can email us anytime at support@modelslab.com

View Docs

Self-hosted on ModelsLab GPUs: FLUX.1 dev (model_id flux), FLUX.1 Kontext dev (flux-kontext-dev), FLUX.2 klein 9B (flux-klein) and FLUX.2 dev (flux-2-dev). From Black Forest Labs on the same key: FLUX1.1 pro, FLUX1.1 pro Ultra, Kontext pro, FLUX.2 pro and FLUX.2 max. There is no first-party FLUX.1 schnell endpoint. You switch models with model_id.

Self-hosted FLUX models list at $0.0047 per image (FLUX.2 dev at $0.02 per megapixel), drawn from a plan: Basic $21/month for 3,250 calls, Standard $47/month for 10,000. The $149/month Open Source Unlimited plan removes the per-image charge on them, about $0.0015 per image at 100,000 images a month. Pro models from Black Forest Labs bill per image from $0.048. Checked September 23, 2026.

Send a POST request to https://modelslab.com/api/v7/images/text-to-image with your API key, model_id set to "flux" (or a specific variant), and a prompt. The response returns hosted image URLs in JSON within 2-4 seconds. Python, JavaScript, and cURL examples are documented at docs.modelslab.com.

Yes. You can attach FLUX LoRAs to steer style, and you can train and deploy your own FLUX LoRAs through the API. Custom LoRAs run through the same text-to-image endpoint by referencing them in the request, so branded or subject-specific pipelines work without extra infrastructure.

Yes. FLUX.1 Kontext is an image-editing model: send an input image plus an instruction prompt and it applies the edit while preserving the rest of the scene. It is available through the same ModelsLab image API, so text-to-image generation and Kontext-based editing share one API key.

ModelsLab is paid-only. The Basic plan is $21/month for 3,250 API calls and can call every FLUX model on the API. The $47/month Standard plan covers 10,000 calls, and Open Source Unlimited at $149/month suits volumes above about 30,000 images a month.

Yes. Black Forest Labs sells its FLUX pro models through its own API, at $0.04 per image for FLUX1.1 [pro] (checked September 23, 2026), and hosts such as ModelsLab, fal.ai, Replicate and Together AI also serve FLUX. On ModelsLab every FLUX model is a model_id on POST https://modelslab.com/api/v7/images/text-to-image.

Yes. ModelsLab serves FLUX.2 dev (flux-2-dev, $0.02 per megapixel) and FLUX.2 klein 9B (flux-klein, $0.0047 per image) on its own GPUs, and FLUX.2 pro ($0.054) and FLUX.2 max ($0.24) from Black Forest Labs. Direct from BFL, FLUX.2 pro starts at $0.03 and Together AI lists FLUX.2 dev at $0.0154 (checked September 23, 2026).

FLUX.1 Kontext dev is self-hosted on ModelsLab at $0.0047 per image and is included in Open Source Unlimited. FLUX.1 Kontext pro is $0.048 per image on ModelsLab and $0.04 direct from Black Forest Labs, fal.ai or Replicate (checked September 23, 2026).

It depends on the variant. FLUX.1 schnell is $0.003 per image on fal.ai and Replicate. FLUX.1 dev is cheapest at volume on the ModelsLab $149/month Open Source Unlimited plan, about $0.0015 per image at 100,000 a month. FLUX1.1 pro and Kontext pro are $0.04 direct from BFL, fal.ai or Replicate. Prices checked September 23, 2026.