Flux Kontext API Tutorial: Generate AI Images in 3 Lines of Code (Python + JavaScript 2026)

What is Flux Kontext?

Flux Kontextis Black Forest Labs' latest model that combines text-to-image generation with context-aware image editing. It understands complex editing instructions and preserves what you want while changing what you specify.

• Context preservation: Keeps what you want, changes what you specify
• Fast generation: ~2.3 seconds average processing time
• High quality: 1024x1024 default, multiple aspect ratios
• Text understanding: Accurate interpretation of complex prompts

Pricing: Why NexaAPI Wins

Setup (30 Seconds)

pip install nexaapi

npm install nexaapi

Python: 3 Lines of Code

# pip install nexaapi
from nexaapi import NexaAPI

client = NexaAPI(api_key='YOUR_API_KEY')

# Generate an image using Flux Kontext
response = client.image.generate(
    model='flux-kontext',
    prompt='A futuristic cityscape at sunset, ultra-detailed, 8K resolution',
    width=1024,
    height=1024,
    num_images=1
)

print(response.image_url)
# Output: https://cdn.nexa-api.com/generated/your-image.png

JavaScript Example

// npm install nexaapi
import NexaAPI from 'nexaapi';

const client = new NexaAPI({ apiKey: 'YOUR_API_KEY' });

async function generateFluxKontextImage() {
  const response = await client.image.generate({
    model: 'flux-kontext',
    prompt: 'A futuristic cityscape at sunset, ultra-detailed, 8K resolution',
    width: 1024,
    height: 1024,
    numImages: 1
  });

  console.log(response.imageUrl);
  // Output: https://cdn.nexa-api.com/generated/your-image.png
}

generateFluxKontextImage();

Advanced: Context-Aware Image Editing

Flux Kontext's standout feature is its ability to edit images using natural language descriptions:

# Edit an existing image with text instructions
edited = client.image.generate(
    model='flux-kontext',
    prompt='Change the background to a snowy mountain landscape, keep the subject the same',
    width=1024,
    height=1024,
    reference_image='https://your-image-url.com/original.jpg'
)
print(edited.image_url)

# Style transfer
styled = client.image.generate(
    model='flux-kontext',
    prompt='Transform this into a watercolor painting style, vibrant colors',
    width=1024,
    height=1024
)
print(styled.image_url)

Batch Generation

prompts = [
    'Minimalist product packaging design, white background',
    'Cyberpunk street market at night, neon lights',
    'Abstract geometric art, vibrant primary colors'
]

# $0.003 × 3 = $0.009 total
for prompt in prompts:
    result = client.image.generate(
        model='flux-kontext',
        prompt=prompt,
        width=1024,
        height=1024
    )
    print(result.image_url)