Image · Black Forest Labs

Flux 2 API

Flux 2 API access for text-to-image and remix-image with strong prompt adherence from Black Forest Labs.

Operational · 4 variants · from $0.050

runapi.ai

curl -X POST https://runapi.ai/api/v1/flux_2/remix_image \
  -H "Authorization: Bearer $RUNAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "flux-2-flex-text-to-image",
  "prompt": "Generate a photorealistic studio portrait of an astronaut holding a cat, dramatic rim lighting, 8K detail."
}'

import { Flux2Client } from "@runapi.ai/flux-2";

const client = new Flux2Client();
const result = await client.remixImage.run({
    model: "flux-2-flex-text-to-image",
    prompt: "Generate a photorealistic studio portrait of an astronaut holding a cat, dramatic rim lighting, 8K detail.",
});

<?php

require __DIR__ . "/vendor/autoload.php";

use RunApi\Flux2\Flux2Client;

$client = new Flux2Client();
$result = $client->remixImage->run([
        'model' => 'flux-2-flex-text-to-image',
        'prompt' => 'Generate a photorealistic studio portrait of an astronaut holding a cat, dramatic rim lighting, 8K detail.',
]);

require "runapi/flux_2"

client = RunApi::Flux2::Client.new
result = client.remix_image.run(
    model: "flux-2-flex-text-to-image",
    prompt: "Generate a photorealistic studio portrait of an astronaut holding a cat, dramatic rim lighting, 8K detail."
)

npx skills add runapi-ai/flux-2 -g

# Claude Code
claude mcp add runapi -s user -- npx -y @runapi.ai/mcp

# Codex
codex plugin install runapi-mcp@agents

# Cursor / Windsurf / VS Code
npx @runapi.ai/mcp init cursor

@runapi.ai/flux-2 v1

OVERVIEW

Flux 2 is Black Forest Labs' text-to-image and image remix model known for strong prompt adherence and high visual fidelity. It supports flexible and pro tiers optimized for speed and quality respectively.

Multiple variants for different speed, quality, and cost tiers
Model skill includes docs, schemas, pricing, and setup notes
Works with Claude Code, Codex, Gemini CLI, Cursor, and VS Code
Single API key and unified billing across all variants
Async task management with polling and webhook callbacks
Failed generations are not charged

VARIANTS

Compare all API variants

Variant	Billing	From
flux-2-flex-remix-image	call	$0.140	View →
flux-2-flex-text-to-image	call	$0.140	View →
flux-2-pro-remix-image	call	$0.050	View →
flux-2-pro-text-to-image	call	$0.050	View →

SKILLS

Install the Flux 2 skill for app development

Load the model docs, schemas, pricing notes, and setup steps into your coding workspace.

# Install the model skill for app development workflows
npx skills add runapi-ai/flux-2 -g

Installs docs, schemas, pricing context, and setup notes into your developer workspace.

Or use this setup request in your coding tool:

Install the Flux 2 skill for this app:

1. Add runapi-ai/flux-2 with the skills installer.
2. Load SKILL.md in this workspace.
3. Use its docs, schemas, pricing notes, and setup steps when adding model features.
4. Confirm the install path when done.

OpenClaw

Use Flux 2 in OpenClaw

Prompt, curl command, parameters, and FAQ.

Hermes Agent

Use Flux 2 in Hermes Agent

Custom provider setup, API call, and FAQ.

HOW IT WORKS

From model skill to first result in four steps

Choose a model

Browse the model catalog and pick the model and variant that match your output type, quality bar, and latency target. Each variant page shows its model ID, pricing, and parameter constraints so you can compare before committing.

Configure

Set your RunAPI API key as an environment variable and install the model skill in your coding workspace. The skill loads docs, typed schemas, pricing notes, and setup steps so your agent has the right context from the start.

Call

Use the skill instructions to add the model feature inside your application. Send a POST request with your prompt, model ID, and parameters. RunAPI routes the request, manages the async lifecycle, and returns structured JSON.

Receive

Poll by task ID for completion, stream results end-to-end when supported, or configure a webhook callback URL to receive results automatically. The CLI provides a built-in wait command, and the SDKs offer both polling and callback patterns.

CONTEXT

What is the Flux 2 API?

Flux 2 is Black Forest Labs' generation model, delivering high prompt adherence across text-to-image and remix-image tasks. Through RunAPI, Pro and Flex variants share the same API shape.

Provider

Black Forest Labs

Modality

Image

WHY RUNAPI

Why route the Flux 2 API through RunAPI

One auth, every provider

A single RunAPI API key unlocks the whole model catalog across all providers. No separate accounts to create, no API keys to rotate per integration, and no credential management overhead. Add a new model to your app by changing one parameter.

Unified pricing & billing

Per-call pricing in USD, billed monthly into a single invoice. No subscription tiers, no minimum spend, and failed generations are never charged. The pricing page and check_pricing API show exact costs before you commit to a model.

Schema-first SDK

Typed schemas, parameter constraints, and setup notes are packaged in the model skill so your implementation starts from the right contract. The skill loads into Claude Code, Codex, Gemini CLI, Cursor, and VS Code — your agent knows the correct request shape before you write a line of code.

FAQ