The CryptoAPIs Signer is a robust MCP (Model Context Protocol) server designed for securely signing blockchain transactions entirely on your local machine. It supports a wide range of networks including EVM (Ethereum, BSC, Polygon, etc.), UTXO (Bitcoin, Litecoin, etc.), Tron, and XRP, ensuring private keys never leave your environment. Emphasizing security, it operates via standard input/output (stdio) with no HTTP transport and requires private keys as direct tool input, never relying on environment variables or making network calls for signing. This tool is ideal for integrating secure, local signing into AI assistants like Claude Desktop or development environments like Cursor, delivering signed transaction hexes ready for broadcast.
Key Features
01No API key required
020 GitHub stars
03Local-only transaction signing (no network calls)
04Supports EVM, UTXO, Tron, and XRP blockchains
05Enhanced security: stdio-only, private keys as direct input, no environment variables
06Versatile signing actions: sign from structured details or unsigned transaction hex
Use Cases
01Integrating secure, local blockchain transaction signing into AI assistants (e.g., Claude Desktop)
02Enabling local transaction signing within development environments (e.g., Cursor)
03Performing offline or highly secure signing for various blockchain transactions
