"National Rail" matching MCP servers:

Spending limits for AI agents. Create budgets, enforce limits, track spend across x402, cards, MPP, or any payment rail.

Provides MCP-callable workflow rails for agents, enabling bounded work execution, movement-fee quotes, payment authority references, paid rail runs, and signed receipts.

Enables AI agents to issue, query, and cancel Serbia SEF eFaktura electronic invoices (UBL 2.1 SRB-CIUS) into the national Ministry of Finance system, using the merchant's own API key.

RailRouter Lite is a real, production-ready MCP server implementing the Model Context Protocol. It exposes one tool: route_payment. This tool intelligently routes payments to the optimal rail (Stripe MPP, Coinbase x402, or Google AP2) in real time, choosing based on cost, latency, and success rate. Every decision is logged to a Cloudflare D1 database, creating compounding routing intelligence

MCP server that lets AI agents create reviewable physical mail drafts, validate quotes, and pay for postage via MPP or x402 protocols.

One API key and one billing rail for hundreds of API tools across many providers — exposed to AI agents through a single MCP endpoint and billed per call with x402 crypto payments.

Enables AI agents to create and manage kankan.email mailboxes, send and receive emails, renew mailboxes, and handle order payments and status queries through MCP tools.

MCP server that provides AI agents a prepaid fiat wallet, enabling them to pay metered APIs per call on the peage rail with adjustable spending caps.

MCP server for noui.bot Agent Bazaar — agent-first infrastructure tools. Platform stats, service discovery, deploy rail, and feedback reporting. Install via npx -y @forthebots/mcp-server.

Universal agentic payment router that gives AI agents the ability to pay across multiple payment rails through a single MCP interface, with cross-rail budget enforcement and a unified audit trail.