Image

Flux 2 Flex API

Black Forest Labs' developer-controlled member of the Flux 2 family (Nov 2025), built for typography and fine detail, with manual control over the quality, speed, and cost of every generation.

Get API key Read the docs

4MP
Max resolution: ~18s
Avg. generation: 4 credits
From

Flux 2 Flex kombucha bottle label mockup reading 'WILD GINGER' with 'Organic, 330ml' beneath in crisp small text

Playground

Try Flux 2 Flex right here.

model: flux-2-flex

Prompt

Aspect ratio Resolution

Image strength

Media inputs

Reference image

Advanced settings

Steps Guidance Output format Output quality Prompt upsampling Let the model rewrite your prompt for better quality. Go fast Seed

Estimated cost 4–30 credits · $0.04–$0.30 Generate in Studio

Output

Your output lands here. Hit generate to run this request in Studio.

Pricing

Simple per-generation pricing.

4–30 credits per generation ≈ $0.04–$0.30

The rate depends on the resolution and options you pick.

You only pay for successful generations. Failed jobs are refunded automatically.
One credit balance across every model on Apiframe, no per-model plans.
Start with free credits. No subscription required.
Volume discounts on larger plans.

See plans and credit packs

Specs

At a glance.

Provider Black Forest Labs

Model ID flux-2-flex

Aspect ratios 1:1, 3:4, 4:3, 9:16, 16:9

Resolutions 0.5MP, 1MP, 2MP, 4MP

Image input Supported

Avg. time ~18s

Quickstart

How to call the Flux 2 Flex API.

Send one POST /v2/images/generate request with your API key. The call returns a jobId you can poll, or pass a webhook_url and the result is pushed to you the moment it's ready.

Swap flux-2-flex for any other model and nothing else changes.

Get API key Read the docs

generate.js

const response = await fetch("https://api.apiframe.ai/v2/images/generate", {
  method: "POST",
  headers: {
    "X-API-Key": "afk_your_api_key_here",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "prompt": "a sleek silver sports car on a coastal highway at sunset, hyper-realistic",
    "model": "flux-2-flex",
    "fluxParams": {
      "resolution": "2MP",
      "image_prompt": "https://example.com/input.jpg",
      "image_prompt_strength": 0.5,
      "steps": 28
    }
  }),
});
const { jobId } = await response.json();
console.log(jobId);

import requests

response = requests.post(
    "https://api.apiframe.ai/v2/images/generate",
    headers={
        "X-API-Key": "afk_your_api_key_here",
        "Content-Type": "application/json",
    },
    json={
        "prompt": "a sleek silver sports car on a coastal highway at sunset, hyper-realistic",
        "model": "flux-2-flex",
        "fluxParams": {
            "resolution": "2MP",
            "image_prompt": "https://example.com/input.jpg",
            "image_prompt_strength": 0.5,
            "steps": 28
        }
    },
)
print(response.json())  # { "jobId": "...", "status": "QUEUED" }

curl -X POST https://api.apiframe.ai/v2/images/generate \
  -H "X-API-Key: afk_your_api_key_here" \
  -H "Content-Type: application/json" \
  -d '{
        "prompt": "a sleek silver sports car on a coastal highway at sunset, hyper-realistic",
        "model": "flux-2-flex",
        "fluxParams": {
            "resolution": "2MP",
            "image_prompt": "https://example.com/input.jpg",
            "image_prompt_strength": 0.5,
            "steps": 28
        }
    }'

let job;
do {
  await new Promise((r) => setTimeout(r, 2000));
  job = await fetch("https://api.apiframe.ai/v2/jobs/JOB_ID", {
    headers: { "X-API-Key": "afk_your_api_key_here" },
  }).then((r) => r.json());
} while (job.status !== "COMPLETED" && job.status !== "FAILED");
console.log(job.result);

import requests, time

while True:
    job = requests.get(
        "https://api.apiframe.ai/v2/jobs/JOB_ID",
        headers={"X-API-Key": "afk_your_api_key_here"},
    ).json()
    if job["status"] in ("COMPLETED", "FAILED"):
        break
    time.sleep(2)
print(job["result"])

curl https://api.apiframe.ai/v2/jobs/JOB_ID \
  -H "X-API-Key: afk_your_api_key_here"

Input schema

Every field Flux 2 Flex accepts, with types and defaults. The full reference lives in the docs.

Field	Type	Description
prompt required	string	Text description of what to generate.
model required	string	The model identifier for this endpoint. Default:"flux-2-flex" · "flux-2-flex"
fluxParams.resolution	string	Resolution Default:"2MP" · "0.5MP", "1MP", "2MP", "4MP"
fluxParams.image_prompt	string (URL)	Reference image (URL)
fluxParams.image_prompt_strength	number	How closely to follow the reference image (0–1). Default:0.5 · min 0, max 1, step 0.05
fluxParams.steps	number	Steps Default:28 · min 1, max 50, step 1
fluxParams.guidance	number	How strictly to follow the prompt. Default:3 · min 1.5, max 10, step 0.1
fluxParams.output_format	string	Output format Default:"jpg" · "jpg", "png", "webp"
fluxParams.output_quality	number	Output quality Default:90 · min 0, max 100, step 1
fluxParams.prompt_upsampling	boolean	Let the model rewrite your prompt for better quality. Default:false
fluxParams.go_fast	boolean	Go fast Default:false
fluxParams.seed	number	Reuse a number to reproduce the same result. step 1

The Flux flagship

Flux 2 Flex is one of 7 Flux image models on Apiframe. The full editorial page (showcase, comparison, and use cases) lives on the flagship.

Flagship from 7 cr Flux 2 Max

The quality ceiling of the Flux family.

Explore Flux 2 Max All image models

Flux 2 Flex questions

What teams ask before shipping with Flux 2 Flex. Everything else lives in the docs.

How is it different from Flux 2 Pro?

Flex exposes the inference steps and guidance scale for manual control, while Pro auto-tunes them for hands-off production. Flex sits at a higher price point and leans toward typography and detail work.

How much does it cost?

On Apiframe it ranges from 4 credits ($0.04) at 0.5MP to 30 credits ($0.30) at 4MP.

What do the steps and guidance settings actually do?

Steps act as a quality dial that trades speed for detail, and guidance scale controls how literally the model follows your prompt.

How many reference images can it use?

Up to 10 at once, totaling 14MP of input.

Can it edit images, not just generate them?

Yes, it supports both text-to-image generation and editing at up to 4MP.

Where can you access it?

Through Apiframe, as well as the BFL API and major hosting partners.