API Overview

Technical reference for the xpay✦ Tools MCP API.

Base URL


https://mcp.xpay.sh/mcp

All endpoints use the MCP JSON-RPC protocol over Streamable HTTP.

Authentication

Pass your API key as a query parameter:


https://mcp.xpay.sh/mcp?key=YOUR_API_KEY

API keys start with xpay_sk_ and can be created at xpay.tools → Account → API Keys.

Protocol

All requests use the MCP protocol (JSON-RPC 2.0):


curl -X POST "https://mcp.xpay.sh/mcp?key=YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"tools/list","id":1}'

Standard MCP Methods

Method	Description
`initialize`	Initialize the MCP session
`tools/list`	List available tools
`tools/call`	Call a tool

Error Codes

Code	Error	Description
401	`UNAUTHORIZED`	Invalid or missing API key
402	`INSUFFICIENT_BALANCE`	Not enough credits for this call
403	`SPENDING_LIMIT_EXCEEDED`	API key spending limit reached
429	`RATE_LIMITED`	Too many requests
500	`UPSTREAM_ERROR`	The provider’s server returned an error
502	`UPSTREAM_UNAVAILABLE`	The provider’s server is unreachable

Rate Limits

Default: 60 requests per minute per API key
Burst: Up to 10 concurrent requests
Rate limit headers are included in responses

Content Type

All requests and responses use Content-Type: application/json.

Further Reference

Connection URLs — URL patterns for master, provider, and collection endpoints
Meta-Tools — Detailed docs for xpay_discover, xpay_details, xpay_run, xpay_balance