polymerdao/polymer-pay-x402engine-image

x402engine Image

x402engine provides pay-per-call AI image generation endpoints. Choose between fast generation (FLUX Schnell), high-quality output (FLUX.2 Pro), or text-in-image rendering (Ideogram v3). No API key needed — payment is handled automatically by the Polymer Pay proxy.

Authentication

All requests route through the Polymer Pay proxy. Include your Polymer Pay API key in every request:

{
  "headers": {
    "Content-Type": "application/json",
    "x-polymer-pay-api-key": "{{POLYMER_PAY_API_KEY}}"
  }
}

Base URL: https://pay.polymerlabs.org/proxy/https/x402engine.app

To get an Polymer Pay API key, sign up at https://my.pay.polymerlabs.org/dashboard/api-keys.

Common Operations

Fast Image Generation (FLUX Schnell)

Generate an image quickly for prototyping and drafts.

Pricing: $0.015

{
  "method": "POST",
  "url": "https://pay.polymerlabs.org/proxy/https/x402engine.app/api/image/fast",
  "headers": {
    "Content-Type": "application/json",
    "x-polymer-pay-api-key": "{{POLYMER_PAY_API_KEY}}"
  },
  "body": {
    "prompt": "A serene mountain landscape at dawn with mist in the valleys"
  }
}

Response: Returns the generated image data (PNG/JPEG).

Quality Image Generation (FLUX.2 Pro)

Generate a higher-quality image for production use.

Pricing: $0.05

{
  "method": "POST",
  "url": "https://pay.polymerlabs.org/proxy/https/x402engine.app/api/image/quality",
  "headers": {
    "Content-Type": "application/json",
    "x-polymer-pay-api-key": "{{POLYMER_PAY_API_KEY}}"
  },
  "body": {
    "prompt": "Professional product photo of a luxury watch on marble surface, studio lighting"
  }
}

Response: Returns a higher-quality generated image with better detail and coherence.

Text-in-Image Generation (Ideogram v3)

Generate an image with accurately rendered text, ideal for logos, signs, and typography.

Pricing: $0.12

{
  "method": "POST",
  "url": "https://pay.polymerlabs.org/proxy/https/x402engine.app/api/image/text",
  "headers": {
    "Content-Type": "application/json",
    "x-polymer-pay-api-key": "{{POLYMER_PAY_API_KEY}}"
  },
  "body": {
    "prompt": "A neon sign that reads OPEN 24 HOURS on a dark brick wall"
  }
}

Response: Returns an image with accurately rendered text.

When to Use

• Quick generation — User wants a fast image generated for prototyping (use /api/image/fast)
• Quality output — User wants production-quality image output (use /api/image/quality)
• Text in image — User needs text rendered inside an image, like logos or signage (use /api/image/text)
• FLUX specifically — User asks for FLUX, Schnell, or Ideogram specifically
• Budget-conscious — User wants the cheapest image generation option

Best Practices

• Fast for drafts — The fast endpoint ($0.015) is ideal for prototyping and drafts — generates in ~2 seconds
• Quality for production — The quality endpoint ($0.05) is ideal for production use with significantly better detail
• Text specialized — The text endpoint ($0.12) is specialized for readable text in images — use only when text rendering is needed
• Descriptive prompts — Keep prompts descriptive for best results
• Save output — All endpoints return image data; save output to a file with -o output.png
• For errors — See @skills/polymer-pay-api-errors/SKILL.md for complete error code reference and troubleshooting