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fastx402

fastx402

Local
github.com/tusk80Developer Tools0Updated 2w ago
Repository

About fastx402

fastx402 is an MCP server offering a catalog of small utilities for AI agents, from data conversion and date tools to crypto and web lookups. It pays per successful call in USDC on Base or Solana, with configurable per-call and daily spending limits.

Key features

  1. 0180+ utility tools
  2. 02Data and media conversion
  3. 03Date, time, and unit utilities
  4. 04IP, DNS, and validation checks
  5. 05Crypto and web lookups
  6. 06Per-call and daily spending caps

Use cases

  1. 01Converting images, video, and structured data
  2. 02Checking dates, time zones, and units
  3. 03Looking up blockchain balances and transactions
  4. 04Fetching webpage text or extracting PDF text

MCP support

Exposes fastx402.tools utilities as MCP tools. The server handles x402 payment requests using a locally held wallet key for USDC payments on Base or Solana.

Configuration

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

mcp.json · Universal config
{
  "mcpServers": {
    "tusk80-fastx402": {
      "command": "npx",
      "args": [
        "-y",
        "fastx402-mcp"
      ],
      "env": {
        "FASTX402_EVM_PRIVATE_KEY": "<FASTX402_EVM_PRIVATE_KEY>",
        "FASTX402_SOLANA_PRIVATE_KEY": "<FASTX402_SOLANA_PRIVATE_KEY>",
        "FASTX402_MAX_USD_PER_CALL": "<FASTX402_MAX_USD_PER_CALL>",
        "FASTX402_MAX_USD_PER_DAY": "<FASTX402_MAX_USD_PER_DAY>"
      }
    }
  }
}
Run commandnpx -y fastx402-mcp
Environment variables to set
FASTX402_EVM_PRIVATE_KEYSecretDedicated wallet key that pays in USDC on Base (0x + 64 hex)
FASTX402_SOLANA_PRIVATE_KEYSecretDedicated wallet key that pays in USDC on Solana (base58)
FASTX402_MAX_USD_PER_CALLMaximum USD per single payment (default 0.05)
FASTX402_MAX_USD_PER_DAYMaximum USD spent per day (default 1)

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
npmfastx402-mcp0.1.1

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

fastx402-mcp

80+ small, fast tools for your AI agent, paid per call in USDC with x402. No account, no API key, no subscription: your agent pays a fraction of a cent per successful call, on Base or Solana.

Tools include background removal, image to SVG, image and video conversion, video to GIF, text to speech, QR codes, YAML/XML/CSV/JSON conversion, Markdown to HTML, text diffs, date math and formatting, cron descriptions, time zones, color conversion, unit conversion, IP and DNS lookups, email/IBAN/ISBN validation, hashing and JWT decoding, Ethereum/Base/Solana balances, token info, transaction status, gas prices, ENS and Basename resolution, web page text, screenshots, PDF text, OCR and audio transcription. The list is read live from fastx402.tools, so new tools appear without updating this package.

Quick start

Claude Desktop, one click: download fastx402.mcpb from the latest release, double-click it, and fill in the form (wallet key and limits). Done.

Any MCP client, by config:

Create a new, dedicated wallet and put a few dollars of USDC in it (on Base, or on Solana). Never use your main wallet.

Claude Desktop (claude_desktop_config.json), Cursor (~/.cursor/mcp.json) and most MCP clients:

{
  "mcpServers": {
    "fastx402": {
      "command": "npx",
      "args": ["-y", "fastx402-mcp"],
      "env": {
        "FASTX402_EVM_PRIVATE_KEY": "0xYOUR_DEDICATED_WALLET_KEY",
        "FASTX402_MAX_USD_PER_DAY": "1"
      }
    }
  }
}

For Solana, set FASTX402_SOLANA_PRIVATE_KEY (base58 secret key) instead of, or next to, the EVM key.

Settings

VariableDefaultWhat it does
FASTX402_EVM_PRIVATE_KEYnoneWallet that pays in USDC on Base (0x + 64 hex)
FASTX402_SOLANA_PRIVATE_KEYnoneWallet that pays in USDC on Solana (base58, 64-byte secret key)
FASTX402_MAX_USD_PER_CALL0.05Refuses any single payment above this, whatever the server asks
FASTX402_MAX_USD_PER_DAY1Stops paying once this much was spent today (kept in ~/.fastx402-mcp/spend.json)
FASTX402_URLhttps://fastx402.toolsThe shop to use

Without a key the server still lists every tool, so you can look before you pay.

How paying works

  1. The agent calls a tool; the server sends the request to fastx402.tools.
  2. The shop answers 402 Payment Required with the exact price.
  3. Your key signs a USDC authorization for that amount only, locally. The key never leaves your machine.
  4. The request is repeated with the signature; the facilitator settles it on-chain (it also pays the network fee) and the answer comes back.

Failed calls (bad input 400, source down 502) are not charged. Prices are shown in every tool description.

Safety

  • Use a dedicated wallet with a small balance; the limits above are a second line of defence.
  • The key is only used to sign x402 USDC payments to fastx402.tools for the listed price.
  • Source: this single file, index.js. Read it.

Links

MIT License.

Comments

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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.