models/Black Forest Labs/Flux-2-Klein-4b

Flux-2-Klein-4b

image

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.

slug · black-forest-labs/flux-2-klein-4bprovider · Black Forest Labsfamily · Fluxreleased · 2026-01-14

Quickstart

curl https://api.aigateway.sh/v1/images/generations \
  -H "Authorization: Bearer $AIGATEWAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"black-forest-labs/flux-2-klein-4b","prompt":"a cyberpunk cat"}'

Capabilities

Strengths

  • Text-to-image generation

Use cases

IllustrationConcept artMarketing assets

Pricing

Per image$0
You pay pass-through · 5% applied at credit top-up, not per-call.
Try in playground →CompareAPI referenceSee usage ranking →

Collections

More image models →More from Black Forest LabsFrontier models →Free-tier models →
API schema

Call Flux-2-Klein-4b from any OpenAI SDK

POST https://api.aigateway.sh/v1/images/generations·Content-Type: application/json·Auth: Bearer sk-aig-...

Request body

json
{
  "model": "black-forest-labs/flux-2-klein-4b",
  "prompt": "A cyberpunk cat at sunset, cinematic lighting",
  "n": 1,
  "size": "1024x1024",
  "response_format": "url"   // or "b64_json"
}

Response

json
{
  "created": 1776947082,
  "data": [
    { "url": "https://media.aigateway.sh/img/abc123.png" }
    // or { "b64_json": "iVBORw0KGgoAAAANSUhEU..." }
  ]
}

Quickstart

from openai import OpenAI
client = OpenAI(base_url="https://api.aigateway.sh/v1", api_key="sk-aig-...")

r = client.images.generate(
    model="black-forest-labs/flux-2-klein-4b",
    prompt="a cyberpunk cat at sunset",
    size="1024x1024",
)
print(r.data[0].url)

Errors

401authentication_errorInvalid or missing API key
402insufficient_creditsWallet empty (PAYG only)
404not_foundUnknown model or endpoint
429rate_limit_errorOver per-minute limit — see Retry-After header
500server_errorUpstream provider failed (retryable)
503service_unavailableUpstream saturated (retryable)
Full docs →API reference →OpenAPI spec →llms.txt →