x402engine — Pay-per-call APIs for AI Agents

# x402engine > Pay-per-call API gateway for AI agents. 113 tools, instant stablecoin payments, no subscriptions. ## What is this? x402engine is an API gateway that provides 113 pay-per-call tools for AI agents using the HTTP 402 payment protocol. LLM calls have request-specific prepaid quotes; other services have listed prices, paid instantly with stablecoins (USDC on Base, USDC on Solana, or USDm on MegaETH). ## How to connect - MCP server (recommended): `npx -y x402engine-mcp` - Remote MCP endpoint: https://x402engine.app/mcp - REST API base: https://x402engine.app - Discovery: https://x402engine.app/.well-known/x402.json - Discovery alias: https://x402engine.app/.well-known/x402 - Agent card: https://x402engine.app/.well-known/agent-card.json - OpenAPI: https://x402engine.app/openapi.json ## Available tools ### Image Generation - generate_image (fast): $0.015 — AI image generation, fast mode - generate_image (quality): $0.05 — AI image generation, quality mode - generate_image (text): $0.12 — AI image with embedded text - face_swap: $0.08 — identity-preserving face swap via FLUX PuLID; requires `reference_image_url` - generate_image (nano-banana): $0.10 — Google's Nano Banana 2, fast high-quality with aspect ratio control ### Video Generation - generate_video (fast): $0.55 — 5-second Kling V3 Standard text-to-video; `/api/video/fast` - generate_video (quality): $0.70 — 5-second Kling V3 Pro text-to-video; `/api/video/quality` - generate_video (Hailuo): $0.65 — 1080p MiniMax Hailuo 2.3 Pro; `/api/video/hailuo` - animate_image: $0.70 — 5-second Kling V3 Pro image-to-video; `/api/video/animate` ### Code Execution - execute_code: $0.005 — Sandboxed code execution (Python, JS, Bash, R, Ruby, Go, Rust) ### Audio - transcribe_audio: $0.10 — Audio transcription (Deepgram Nova-3) - text_to_speech (OpenAI): $0.01 — Text-to-speech via OpenAI - text_to_speech (ElevenLabs): $0.02 — Text-to-speech via ElevenLabs - voice_clone_tts (Lux): $0.02