Flux 2 Pro API in JavaScript — Quick Start Guide 2026

# For Node.js 18+, no installation needed!
# For older Node.js versions:
npm install node-fetch

# TypeScript users (optional type definitions):
npm install --save-dev @types/node

// flux2pro-generate.js
// Works with Node.js 18+ (native fetch) or browser environments

const RAPIDAPI_KEY = 'YOUR_RAPIDAPI_KEY'; // Replace with your key
const API_HOST = 'flux-2-pro.p.rapidapi.com';

const generateImage = async (prompt, options = {}) => {
  const response = await fetch(`https://${API_HOST}/generate`, {
    method: 'POST',
    headers: {
      'x-rapidapi-key': RAPIDAPI_KEY,
      'x-rapidapi-host': API_HOST,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      prompt,
      width: options.width || 1024,
      height: options.height || 1024,
      steps: options.steps || 28,
      guidance: options.guidance || 3.5,
      ...options
    })
  });

  if (!response.ok) {
    const error = await response.json();
    throw new Error(`API Error ${response.status}: ${error.message}`);
  }

  const data = await response.json();
  console.log('✅ Image generated successfully!');
  console.log('Image URL:', data.url);
  return data;
};

// Example usage
generateImage('a breathtaking mountain landscape at golden hour, photorealistic, 8K detail')
  .then(result => {
    console.log('Result:', result);
  })
  .catch(err => console.error('Error:', err));

// Advanced configuration example
const advancedGenerate = async () => {
  const result = await generateImage(
    'a futuristic cityscape at night, neon lights, rain-soaked streets, cyberpunk aesthetic',
    {
      width: 1440,          // Up to 2048px
      height: 960,          // Landscape format
      steps: 40,            // More steps = higher quality (20-50)
      guidance: 4.5,        // Prompt adherence (1-10, higher = more literal)
      seed: 42,             // Reproducible results
      output_format: 'png', // 'jpeg', 'png', or 'webp'
    }
  );
  
  return result;
};

// Batch generation with rate limiting
const batchGenerate = async (prompts) => {
  const results = [];
  for (const prompt of prompts) {
    const result = await generateImage(prompt);
    results.push(result);
    // Respect rate limits: add delay between requests
    await new Promise(resolve => setTimeout(resolve, 500));
  }
  return results;
};

// Save image to disk (Node.js)
import { writeFileSync } from 'fs';

const saveImage = async (prompt, filename) => {
  const result = await generateImage(prompt);
  const imageResponse = await fetch(result.url);
  const buffer = await imageResponse.arrayBuffer();
  writeFileSync(filename, Buffer.from(buffer));
  console.log(`Saved to ${filename}`);
};