x402search — Pay-Per-Search API Discovery for AI Agents

Name: x402search — Pay-Per-Search API Discovery for AI Agents
Author: x402-index

Local

github.com/x402-indexDeveloper Tools2Updated 31w ago

Repository

About x402search — Pay-Per-Search API Discovery for AI Agents

x402search is an MCP server for AI agents that discovers x402-enabled HTTP APIs. Searches return endpoint and payment details, with payment made in USDC on Base.

Key features

01Search x402-enabled HTTP APIs
02Filter by network and price
03Limit and rank search results
04Return endpoint and payment metadata

Use cases

01Find an API for token prices
02Discover DeFi and blockchain APIs
03Filter APIs by network or cost

MCP support

Exposes the search_x402_apis tool to MCP clients. Each search costs 0.01 USDC on Base and requires an EVM wallet private key.

#x402 #search #api-discovery #payments #blockchain

Configuration

Local server config is the same for every client. Copy it into your client’s MCP config file.

mcp.json · Universal config

{
  "mcpServers": {
    "x402search": {
      "command": "npx",
      "args": [
        "-y",
        "x402search-mcp"
      ],
      "env": {
        "PRIVATE_KEY": "<PRIVATE_KEY>"
      }
    }
  }
}

Run commandnpx -y x402search-mcp

Environment variables to set

PRIVATE_KEYSecretEVM private key for x402 payment signing

Local servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.

Packages

npmx402search-mcp1.0.2stdio

Tools

No tool list yet

Local servers expose tools only once running on your machine, and the maintainer has not provided a tool list.

Details

From the project README

x402search MCP Server

Search 14,000+ x402-enabled HTTP APIs from any MCP-compatible agent.

Version: 1.0.3 · License: MIT · Cost: $0.01 USDC per search · Base mainnet · No account needed

npm: https://www.npmjs.com/package/x402search-mcp
PyPI: https://pypi.org/project/x402search-mcp
API: https://x402search.xyz

Requirements

A wallet private key (EVM)
USDC on Base mainnet (eip155:8453)
Get USDC on Base: https://www.coinbase.com/how-to-buy/usdc

Install: Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "x402search": {
      "command": "npx",
      "args": ["[email protected]"],
      "env": {
        "EVM_PRIVATE_KEY": "0xYOUR_PRIVATE_KEY_HERE"
      }
    }
  }
}

Config file location:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

Install: Claude Code

claude mcp add x402search -- npx [email protected]

Then set your key:

export EVM_PRIVATE_KEY=0xYOUR_PRIVATE_KEY_HERE

Install: Cursor

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "x402search": {
      "command": "npx",
      "args": ["[email protected]"],
      "env": {
        "EVM_PRIVATE_KEY": "0xYOUR_PRIVATE_KEY_HERE"
      }
    }
  }
}

Install: Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "x402search": {
      "command": "npx",
      "args": ["[email protected]"],
      "env": {
        "EVM_PRIVATE_KEY": "0xYOUR_PRIVATE_KEY_HERE"
      }
    }
  }
}

Install: Python agents (LangChain, CrewAI, AutoGen, GAME SDK)

pip install x402search-mcp

from x402search import search_x402_apis
results = search_x402_apis(
    query="token price API ethereum",
    private_key="0xYOUR_PRIVATE_KEY_HERE"
)
print(results)

Full docs: https://pypi.org/project/x402search-mcp

Quick Test

EVM_PRIVATE_KEY=0xYOUR_KEY npx [email protected]

Tool: search_x402_apis

Parameter	Type	Required	Description
query	string	yes	e.g. "token price API", "DEX swap routing"
network	string	no	e.g. "eip155:8453" for Base mainnet
max_price_usdc	number	no	Filter to APIs at or below this price
limit	number	no	Max results (default 10, max 50)

Virtuals ACP Integration

x402search is available as a native ACP agent on the Virtuals protocol marketplace.

Agent ID: 22531
Agent profile: https://app.virtuals.io/acp/agent-details/22531
Job name: x402search
Price: 0.01 USDC per search
Accepts crypto, DeFi, and blockchain API discovery queries
Rejects off-topic requests automatically at the request phase
Returns structured results: endpoint URLs, payment metadata, network, and relevance rank

Comments

Markdown supported

New to MCP?

From what the protocol is to installing your first server, these answers cover most first questions.

Read the getting-started guide

An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.