x402engine-mcp

MCP server for x402 Engine — giving AI agents access to 38 pay-per-call APIs via HTTP 402 micropayments.

Payments are made with USDC on Base, USDC on Solana, or USDm on MegaETH. Prices range from $0.001 to $0.12 per call.

Quick Start

Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "x402engine": {
      "command": "npx",
      "args": ["-y", "x402engine-mcp"],
      "env": {
        "X402_DEV_BYPASS": "your-dev-bypass-secret"
      }
    }
  }
}

Claude Code

claude mcp add x402engine -- npx -y x402engine-mcp

Available Tools

LLM Inference

| Tool | Price | Description | |------|-------|-------------| | llm_chat | $0.002-$0.09 | Chat completion with any supported model |

Supported models: GPT-4o ($0.04), GPT-4o Mini ($0.003), OpenAI o1 ($0.03), Claude Opus 4.6 ($0.09), Claude Sonnet 4.5 ($0.06), Claude Haiku 4.5 ($0.02), Gemini 2.5 Pro ($0.035), Gemini 2.5 Flash ($0.009), Grok 4 ($0.06), DeepSeek V3 ($0.005), DeepSeek R1 ($0.01), Llama 3.3 70B ($0.002), Mistral Large 3 ($0.006), Qwen3 235B ($0.004), Perplexity Sonar Pro ($0.06).

Image Generation

| Tool | Price | Description | |------|-------|-------------| | generate_image | $0.015-$0.12 | AI image generation (fast/quality/text tiers) |

Code Execution

| Tool | Price | Description | |------|-------|-------------| | execute_code | $0.005 | Sandboxed code execution (Python, JS, Bash, R) |

Audio

| Tool | Price | Description | |------|-------|-------------| | transcribe_audio | $0.10 | Audio-to-text transcription (Deepgram Nova-3) | | tts_openai | $0.01 | Text-to-speech (OpenAI) | | tts_elevenlabs | $0.02 | Text-to-speech (ElevenLabs) |

Text Embeddings

| Tool | Price | Description | |------|-------|-------------| | create_embeddings | $0.001 | Text embeddings (OpenAI text-embedding-3-small) |

Crypto & Market Data

| Tool | Price | Description | |------|-------|-------------| | get_crypto_price | $0.001 | Current crypto prices | | get_crypto_markets | $0.002 | Top coins by market cap | | get_crypto_history | $0.003 | Historical price charts | | get_trending_crypto | $0.001 | Trending coins | | search_crypto | $0.001 | Search for coins |

Blockchain & Wallet

| Tool | Price | Description | |------|-------|-------------| | get_wallet_balances | $0.005 | Token balances for any wallet | | get_wallet_transactions | $0.005 | Transaction history | | get_wallet_pnl | $0.01 | Profit & loss analysis | | get_token_prices | $0.005 | DEX-derived token prices | | get_token_metadata | $0.002 | Token metadata | | simulate_transaction | $0.01 | Transaction simulation (Tenderly) |

Web

| Tool | Price | Description | |------|-------|-------------| | web_scrape | $0.005 | Scrape and extract web page content | | web_screenshot | $0.01 | Capture web page screenshot |

IPFS Storage

| Tool | Price | Description | |------|-------|-------------| | pin_to_ipfs | $0.01 | Pin JSON to IPFS | | get_from_ipfs | $0.001 | Retrieve content from IPFS |

Discovery

| Tool | Price | Description | |------|-------|-------------| | discover_services | Free | List all services and pricing |

Environment Variables

| Variable | Required | Description | |----------|----------|-------------| | X402_BASE_URL | No | Gateway URL (default: https://x402-gateway-production.up.railway.app) | | X402_DEV_BYPASS | No | Dev bypass secret to skip payments | | X402_PAYMENT_HEADER | No | Pre-signed payment header |

Payment Networks

• Base (EVM) — USDC, 6 decimals, ~2s confirmation
• Solana — USDC, 6 decimals, ~400ms confirmation
• MegaETH (EVM) — USDm, 18 decimals, ~10ms confirmation

How It Works

1. Agent calls an MCP tool (e.g., llm_chat)
2. MCP server makes HTTP request to x402engine.app
3. Gateway returns 402 Payment Required with pricing
4. Agent pays with crypto via the x402 protocol
5. Gateway verifies payment on-chain and returns data

For automatic payment handling, use @x402/fetch in your agent code.

Links

• Gateway: x402engine.app
• Discovery: x402engine.app/.well-known/x402.json
• GitHub: github.com/agentc22/x402engine-mcp
• Protocol: x402.org