Black Forest LabsimageNew

FLUX 3 Image Klein Text to Image API

Name: FLUX 3 Image Klein API
Brand: Black Forest Labs
SKU: bfl/flux-3-image-klein
Availability: InStock

Text to Image with FLUX 3 Image Klein by Black Forest Labs. The open-weights FLUX 3 — 16-step images in seconds, from a fraction of a cent.

bfl/flux-3-image-klein/text-to-image

FromUp to −87%

$0.0011/img$0.008

per image · 768

With Max: from $0.001/img →Operational99.86% uptime (30 days)median 12s

Create with FLUX 3 Image Klein Get API key

API docs →Compare models →

Try FLUX 3 Image Klein Text to Image

Prompt*

0/5000

Aspect ratio

Output image shape.

Resolution

Output size tier: 768 ≈ 0.6 MP, 1K ≈ 1 MP, 1.5K ≈ 2.4 MP, 2K ≈ 4 MP, 4K ≈ 16 MP. Up to 2K, wide and tall ratios keep the long side at 2048 px or less; 4K takes 1:1, 4:3, 3:4, 3:2, 2:3, 16:9, 9:16, 21:9, 9:21.

Enable Safety Checker

Always on here. Set enable_safety_checker to false over the API to turn it off.

If set to true, the safety checker will be enabled. Content our Acceptable Use Policy prohibits stays blocked either way.

Estimated cost…

Create a free account with Google or email — pay only for what you generate.

Your image will appear here

Write a prompt, pick your settings and hit Run. You only pay for successful generations.

Also available: FLUX 3 Image Klein Image Edit

See the FLUX 3 Image Klein examples and prompts

FLUX 3 Image Klein Text to Image API

POST/api/v1/run/bfl/flux-3-image-klein/text-to-image

Submits an asynchronous job and returns 202 with a generation id. Poll GET /api/v1/generations/{id} or pass webhook_url. See job lifecycle.

Input parameters

Name	Type	Description	Affects price
`prompt`required	string	Describe the shot: subject, action, camera movement, lighting and style.	No
`aspect_ratio`	string (enum)	Output image shape. Values: 1:1 · 4:5 · 3:4 · 2:3 · 9:16 · 1:2 · 9:21 · 5:4 · 4:3 · 3:2 · 16:9 · 2:1 · 21:9 · 7:5 · 5:7 Default: 1:1	Yes
`resolution`	string (enum)	Output size tier: 768 ≈ 0.6 MP, 1K ≈ 1 MP, 1.5K ≈ 2.4 MP, 2K ≈ 4 MP, 4K ≈ 16 MP. Up to 2K, wide and tall ratios keep the long side at 2048 px or less; 4K takes 1:1, 4:3, 3:4, 3:2, 2:3, 16:9, 9:16, 21:9, 9:21. Values: 768 · 1K · 1.5K · 2K · 4K Default: 1K	Yes
`seed`	integer	Use the same seed and settings to reproduce a result. Leave empty for random.	No
`enable_safety_checker`	boolean	If set to true, the safety checker will be enabled. Content our Acceptable Use Policy prohibits stays blocked either way. Default: true	No
`webhook_url`	string (URL)	Optional. We POST the finished generation here, signed with your webhook secret. Webhooks	No

Request

const API = "https://cheapergen.com/api/v1";
const headers = {
  Authorization: `Bearer ${process.env.CHEAPERGEN_API_KEY}`,
  "Content-Type": "application/json",
};

// 1. Submit the job
let job = await fetch(`${API}/run/bfl/flux-3-image-klein/text-to-image`, {
  method: "POST",
  headers,
  body: JSON.stringify({
    "prompt": "Editorial still life of a hand-thrown terracotta vase with dried orange ranunculus on a travertine plinth, low golden-hour sun from the left, long soft shadows on a warm plaster wall, medium-format film photograph",
    "aspect_ratio": "1:1",
    "resolution": "1K"
  }),
}).then((r) => r.json());

// 2. Poll until it finishes (or pass webhook_url and skip polling)
while (job.status === "queued" || job.status === "running") {
  await new Promise((r) => setTimeout(r, 3000));
  job = await fetch(`${API}/generations/${job.id}`, { headers }).then((r) => r.json());
}

console.log(job.status === "succeeded" ? job.output.images[0].url : job.error);

import os, time, requests

API = "https://cheapergen.com/api/v1"
headers = {"Authorization": f"Bearer {os.environ['CHEAPERGEN_API_KEY']}"}

# 1. Submit the job
job = requests.post(f"{API}/run/bfl/flux-3-image-klein/text-to-image", headers=headers, json={
    "prompt": "Editorial still life of a hand-thrown terracotta vase with dried orange ranunculus on a travertine plinth, low golden-hour sun from the left, long soft shadows on a warm plaster wall, medium-format film photograph",
    "aspect_ratio": "1:1",
    "resolution": "1K"
}).json()

# 2. Poll until it finishes (or pass "webhook_url" and skip polling)
while job["status"] in ("queued", "running"):
    time.sleep(3)
    job = requests.get(f"{API}/generations/{job['id']}", headers=headers).json()

print(job["status"], job["output"]["images"][0]["url"] if job["status"] == "succeeded" else job["error"])

curl -X POST https://cheapergen.com/api/v1/run/bfl/flux-3-image-klein/text-to-image \
  -H "Authorization: Bearer $CHEAPERGEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "prompt": "Editorial still life of a hand-thrown terracotta vase with dried orange ranunculus on a travertine plinth, low golden-hour sun from the left, long soft shadows on a warm plaster wall, medium-format film photograph",
  "aspect_ratio": "1:1",
  "resolution": "1K"
}'

Response

{
  "id": "gen_8c2QmX1nq0k4",
  "object": "generation",
  "model": "bfl/flux-3-image-klein",
  "endpoint": "bfl/flux-3-image-klein/text-to-image",
  "mode": "text-to-image",
  "status": "queued",
  "input": {
    "prompt": "Editorial still life of a hand-thrown terracotta vase with dried orange ranunculus on a travertine plinth, low golden-hour sun from the left, long soft shadows on a warm plaster wall, medium-format film photograph",
    "aspect_ratio": "1:1",
    "resolution": "1K"
  },
  "output": null,
  "error": null,
  "cost": {
    "amount_usd": 0.2255,
    "currency": "usd",
    "estimated": true,
    "official_usd": null,
    "list_price_source": "official",
    "list_price_label": "Official",
    "saved_usd": null
  },
  "source": "api",
  "started_at": null,
  "completed_at": null,
  "urls": {
    "get": "https://cheapergen.com/api/v1/generations/gen_8c2QmX1nq0k4",
    "cancel": "https://cheapergen.com/api/v1/generations/gen_8c2QmX1nq0k4/cancel"
  },
  "created_at": "2026-10-15T09:21:04Z"
}

{
  "id": "gen_8c2QmX1nq0k4",
  "object": "generation",
  "model": "bfl/flux-3-image-klein",
  "endpoint": "bfl/flux-3-image-klein/text-to-image",
  "mode": "text-to-image",
  "status": "succeeded",
  "input": {
    "prompt": "Editorial still life of a hand-thrown terracotta vase with dried orange ranunculus on a travertine plinth, low golden-hour sun from the left, long soft shadows on a warm plaster wall, medium-format film photograph",
    "aspect_ratio": "1:1",
    "resolution": "1K"
  },
  "output": {
    "images": [
      {
        "url": "https://cdn.cheapergen.com/outputs/gen_8c2Q-0.png",
        "content_type": "image/png",
        "width": 2048,
        "height": 2048
      }
    ]
  },
  "error": null,
  "cost": {
    "amount_usd": 0.2255,
    "currency": "usd",
    "estimated": false,
    "official_usd": 0.264,
    "list_price_source": "official",
    "list_price_label": "Official",
    "saved_usd": 0.0385
  },
  "source": "api",
  "created_at": "2026-10-15T09:21:04Z",
  "started_at": "2026-10-15T09:21:06Z",
  "completed_at": "2026-10-15T09:22:31Z"
}

FLUX 3 Image Klein pricing

Pay per image as you go, with no subscription required. Failed generations are refunded automatically.

Tier	Official price	CheaperGen	You save
768 768×768	~~$0.008~~/img	$0.0011/img With a monthly plan: Max $0.001	−87%
1K 1024×1024	~~$0.009~~/img	$0.0019/img With a monthly plan: Pro $0.0018Max $0.0017	−79%
1.5K 1536×1536	~~$0.011~~/img	$0.0043/img With a monthly plan: Pro $0.004Max $0.0038	−61%
2K 2048×2048	~~$0.014~~/img	$0.0074/img With a monthly plan: Pro $0.0069Max $0.0065	−48%
4K ≈16 MP	~~$0.036~~/img	$0.0342/img	−5%
Edit 1K 1–10 reference images	~~$0.009~~/img	$0.0085/img	−6%
Edit 2K 1–10 reference images	~~$0.014~~/img	$0.0133/img	−5%
Edit 4K 1–10 reference images	~~$0.036~~/img	$0.0342/img	−5%

Monthly plans lower prices on most models (shown under each price); you can still pay as you go. Pro $499/month · Max $4,999/month.

Official price: BFL API list price for FLUX 3 Image Klein ($0.008 at 768², $0.009 at 1K, $0.011 at 1.5K, $0.014 at 2K, $0.036 at 4K; BFL charges the same for an edit) — https://docs.bfl.ai/quick_start/pricing#flux-3-image-klein. Prices verified October 18, 2026.
Editing has its own price per output size (the Edit rows: 1K, 2K or 4K), the same however many reference images (up to 10).
Served without BFL's prompt upsampler: your prompt reaches the model as written.