Skip to content
Cloudflare Docs
Black Forest Labs logo

flux-2-klein-4b

Text-to-Image • Black Forest Labs
@cf/black-forest-labs/flux-2-klein-4b

FLUX.2 [klein] is an ultra-fast, distilled image model. It unifies image generation and editing in a single model, delivering state-of-the-art quality enabling interactive workflows, real-time previews, and latency-critical applications.

Model Info
Terms and Licenselink ↗
PartnerYes
Unit Pricing$0.000059 per input 512x512 tile, $0.000287 per output 512x512 tile

Usage

Workers - TypeScript
TypeScript
export interface Env {
  AI: Ai;
}


export default {
  async fetch(request, env): Promise<Response> {
    const form = new FormData();
    form.append('prompt', 'a sunset with a dog');
    form.append('width', '1024');
    form.append('height', '1024');


    const resp = await env.AI.run("@cf/black-forest-labs/flux-2-klein-4b", {
      multipart: {
        body: formStream,
        contentType: formContentType
      }
    });


    return Response.json(resp);
  },
} satisfies ExportedHandler<Env>;

curl
Terminal window
curl --request POST \
  --url 'https://api.cloudflare.com/client/v4/accounts/{ACCOUNT}/ai/run/@cf/black-forest-labs/flux-2-klein-4b' \
  --header 'Authorization: Bearer {TOKEN}' \
  --header 'Content-Type: multipart/form-data' \
  --form 'prompt=a sunset at the alps' \
  --form steps=25 \
  --form width=1024 \
  --form height=1024

Parameters

* indicates a required field

Input

  • multipart object required

    • body object

    • contentType string

Output

  • image string

    Generated image as Base64 string.

API Schemas

The following schemas are based on JSON Schema

{
    "type": "object",
    "properties": {
        "multipart": {
            "type": "object",
            "properties": {
                "body": {
                    "type": "object"
                },
                "contentType": {
                    "type": "string"
                }
            }
        }
    },
    "required": [
        "multipart"
    ]
}