Black Forest Labs FLUX API: FLUX.2-pro image generation and checks

Models and current API429 rates

These are exact image model IDs for this family. The public catalog and GET /v1/models for your key answer different questions: a published entry does not prove account access. Preserve hyphens, dots and versions exactly.

Catalog data date: Oct 25, 2026, 8:27 AM UTC. Rates retain their catalog conditions; an absent row does not mean a free request.

Family pricing and calculator · Full catalog

Choose your next connection step

• FLUX API pricing

  Review megapixel billing units, output_mp and reference_mp conditions, and cost comparisons for FLUX image models.

• API429 model catalog

  Check the literal FLUX.2-pro identifier, image_generation capability and live catalog rate cards.

• API429 quickstart

  Configure your server-side API429 key, check GET /v1/models and review documented API429 endpoints.

First image generation: curl, Python, JavaScript

1. Create a key in your API429 account and add balance by Russian bank card, a business invoice, USDT or TON. A $10 test balance is available for subscribing to the Telegram channel through the bonus bot.
2. Use the same key to verify FLUX.2-pro in GET https://gateway.api429.com/v1/models.
3. Set API429_API_KEY on the server and send a small paid request. The example does not retry automatically.
4. Inspect one output, warnings, parameter_mismatches, api429.outputs and the PNG, JPEG or WebP signature. A timeout does not prove that the operation was unbilled.

The example uses POST /v1/images/generations, n=1, size=1024x1024 and response_format=b64_json without reference images. Do not carry over output_mp rows with reference_mp=0 to reference-image requests. Python and JavaScript verify key access, output count and file signature; warnings and actual visual output still require inspection. For curl, check the model list and JSON response separately.

curl

curl --fail-with-body https://gateway.api429.com/v1/images/generations \
  -H "Authorization: Bearer $API429_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"FLUX.2-pro","prompt":"A ceramic cup on a wooden table, neutral background, soft daylight.","n":1,"size":"1024x1024","response_format":"b64_json"}' \
  --output image-response.json

Python 3

import base64
import json
import os
import urllib.request
from pathlib import Path

key = os.environ["API429_API_KEY"]
base = "https://gateway.api429.com/v1"
headers = {"Authorization": "Bearer " + key, "Content-Type": "application/json"}
model = "FLUX.2-pro"
with urllib.request.urlopen(urllib.request.Request(base + "/models", headers=headers), timeout=30) as response:
    available = {item["id"] for item in json.load(response)["data"]}
if model not in available:
    raise ValueError("Model unavailable to this key")
payload = json.loads("{\"model\":\"FLUX.2-pro\",\"prompt\":\"A ceramic cup on a wooden table, neutral background, soft daylight.\",\"n\":1,\"size\":\"1024x1024\",\"response_format\":\"b64_json\"}")
request = urllib.request.Request(base + "/images/generations",
    data=json.dumps(payload).encode("utf-8"), headers=headers, method="POST")
with urllib.request.urlopen(request, timeout=180) as response:
    result = json.load(response)
if result.get("warnings") or result.get("api429", {}).get("parameter_mismatches"):
    print("Inspect output warnings:", result.get("warnings"), result.get("api429"))
items = result.get("data", [])
if len(items) != 1 or not items[0].get("b64_json"):
    raise ValueError("Missing image or partial result; inspect before retrying")
raw = base64.b64decode(items[0]["b64_json"], validate=True)
if raw.startswith(b"\x89PNG\r\n\x1a\n"):
    extension = "png"
elif raw.startswith(b"\xff\xd8\xff"):
    extension = "jpg"
elif raw.startswith(b"RIFF") and raw[8:12] == b"WEBP":
    extension = "webp"
else:
    raise ValueError("Unknown image MIME; inspect before saving")
Path("image." + extension).write_bytes(raw)
print(result.get("api429", {}).get("outputs"))

JavaScript: Node.js 18+

import { writeFile } from "node:fs/promises";
const key = process.env.API429_API_KEY;
if (!key) throw new Error("Set API429_API_KEY");
const base = "https://gateway.api429.com/v1";
const headers = { Authorization: "Bearer " + key, "Content-Type": "application/json" };
const model = "FLUX.2-pro";
const available = await fetch(base + "/models", { headers, signal: AbortSignal.timeout(30000) });
if (!available.ok) throw new Error("Models HTTP " + available.status);
if (!(await available.json()).data.some(item => item.id === model)) throw new Error("Model unavailable to this key");
const payload = {"model":"FLUX.2-pro","prompt":"A ceramic cup on a wooden table, neutral background, soft daylight.","n":1,"size":"1024x1024","response_format":"b64_json"};
const response = await fetch(base + "/images/generations", {
 method: "POST", headers, body: JSON.stringify(payload), signal: AbortSignal.timeout(180000)
});
if (!response.ok) throw new Error("Generation HTTP " + response.status);
const result = await response.json();
if (result.warnings || result.api429?.parameter_mismatches) console.warn("Inspect warnings", result.warnings, result.api429);
if (result.data?.length !== 1 || !result.data[0].b64_json) throw new Error("Missing image or partial result; inspect before retrying");
const bytes = Buffer.from(result.data[0].b64_json, "base64");
const hex = bytes.subarray(0, 8).toString("hex");
const extension = hex === "89504e470d0a1a0a" ? "png" : hex.startsWith("ffd8ff") ? "jpg" : bytes.toString("ascii", 0, 4) === "RIFF" && bytes.toString("ascii", 8, 12) === "WEBP" ? "webp" : undefined;
if (!extension) throw new Error("Unknown image MIME; inspect before saving");
await writeFile("image." + extension, bytes);
console.log(result.api429?.outputs);

These examples do not prove access for your key; verify the exact ID before a paid request. API contract · Configure your client · Questions and support

Frequently asked questions

Sources and editorial review

Manufacturer documentation describes its family and its own API rules. API429 IDs, rates and request contracts require separate catalog and documentation checks. The original source-review date below is retained; English publication does not renew the source review.

• Black Forest Labs documentation: generating images quickstart
• Black Forest Labs documentation: FLUX.2 overview
• API429 public catalog
• API429 public request contract

Source review: Oct 24, 2026, 12:34 PM UTC. To connect, create an API429 account and follow the quickstart instructions.