INTEGRATION GUIDE

How to Run FLUX Kontext Pro API: Contextual Inpainting & Editing

Q: Can I pass image URLs or base64 data to FLUX Kontext Pro?

Both are supported. You can pass a publicly accessible HTTPS image URL or a standard data:image/png;base64 string in the image parameter.

Q: Does it preserve facial features in portrait edits?

Yes. Kontext Pro retains facial symmetry and skin textures while updating clothing, hairstyles, or backgrounds as described in the prompt.

Learn how to run FLUX Kontext Pro via unified REST API. Seamless contextual inpainting, subject replacement, and high-fidelity prompt obedience at $0.05/run.

Updated Oct 2026 • 6 min read • Verified Production Ready

Inference Cost

$0.050

per generation

Execution Latency

Instant (< 4s)

Warm GPU cluster

Resolution / Quality

Custom Ratios

Lossless output

SDK Protocol

REST / OpenAI

cURL, Python, Node

Architectural Overview

FLUX Kontext Pro specializes in context-aware image generation and localized modification. Unlike traditional diffusion models that hallucinate inconsistent boundaries, Kontext Pro accurately understands lighting, textures, and geometry from surrounding context.

Pricing Breakdown & Benchmark

No monthly base subscriptions, no minimum commitments, and no idle cluster charges. Compare real production costs below:

Model / Task	LumozAI Price	Alternative Providers	Avg Latency	Recommended For
flux-kontext-pro	$0.050 / run	$0.065 / run	4.2s	Inpainting & background swap
step1x-edit	$0.033 / run	$0.045 / run	3.8s	Instruction-based photo edits
picplug	$0.060 / run	$0.080 / run	5.0s	Product photo contextual staging

Code Integration (REST, Python, Node.js)

Execute directly against our high-throughput gateway. Replace YOUR_LUMOZ_API_KEY with your free developer key.

curl -X POST "https://lumozai.com/api/v4/run" \
  -H "Authorization: Bearer YOUR_LUMOZ_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "flux-kontext-pro",
    "prompt": "Replace the office background with a sunlit Scandinavian living room with green monstera plants",
    "image": "https://example.com/source-photo.jpg",
    "aspect_ratio": "1:1"
  }'

import requests

url = "https://lumozai.com/api/v4/run"
headers = {"Authorization": "Bearer YOUR_LUMOZ_API_KEY"}
payload = {
    "model": "flux-kontext-pro",
    "prompt": "Replace background with a modern Tokyo coffee shop interior",
    "image": "https://example.com/input.jpg"
}

resp = requests.post(url, json=payload, headers=headers).json()
print("Contextual output:", resp.get("output"))

const res = await fetch("https://lumozai.com/api/v4/run", {
  method: "POST",
  headers: { "Authorization": "Bearer YOUR_LUMOZ_API_KEY", "Content-Type": "application/json" },
  body: JSON.stringify({
    model: "flux-kontext-pro",
    prompt: "Place the product onto a clean white marble countertop",
    image: "https://example.com/product.png"
  })
});
const result = await res.json();
console.log(result.output);