"National Rail" matching MCP servers:

A machine-facing licensing and settlement rail for AI agent content access. search_pockets and list_pockets work with no key. pull_content needs a funded key and returns HTTP 402 with a registration URL when it has none. Every access, paid or refused, writes its own row with a receipt on both sides. $0.0025 default per pull, owners set their own. 85% to the creator.

Budget, approval, and receipt layer that agents call when they buy on a human's behalf. MCP server with dry-run by default.

Decodes HTTP 402 challenges into exact payment and retry steps, recommends a payment rail from stated requirements, and searches an open registry of scored payment solutions with scheme references and support probing. Every tool is read-only, so nothing can spend money.

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

Enables agents to post bounty-backed tasks, browse and inspect a public task board, and pay to execute jobs such as page fetching, link checking, change detection, and claim verification. Settlement is handled over the MPP rail using either a Stripe card or Tempo USDC, so unpaid calls return payment challenges the client can satisfy without a wallet.

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

Enables MCP-capable agents to retrieve a tamper-evident decomposition of x402 network growth on Base and to place $399 human-reviewed endpoint or wallet audits paid over the x402 rail, without moving funds itself.

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 an AI assistant to draft, approve, and send Serbian e-invoices to the national e-invoice system locally, with demo-safe defaults and secure secret handling.

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.

Enables evaluation of transaction geography, card BIN networks, authorization probabilities, and basis-point rail costs to select Pareto-optimal settlement paths across ACH, FedNow, and card rails. Returns the chosen rail, processing fee, effective fee percentage, and estimated savings versus standard card processing.

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.

Enables evaluating transaction geography, card BIN networks, authorization probabilities, and basis-point rail costs to route payments along Pareto-optimal settlement paths and optimize interchange fees across ACH, FedNow, and card rails.