"Guide to Using LangChain Correctly" matching MCP servers:

Enables AI agents to create and manage sellable listings, handle orders, and integrate Stripe payments through natural language using ListBee's API.

MCP server that gates API calls to AI agents using proof-of-work (free) or Lightning payment (3 sats), providing challenge, verify, and status tools for per-call authentication without accounts.

Connects Claude to the customer side of Housecall Pro, letting you view estimates and invoices, check company details, and decline estimate options using the link your contractor sent.

Enables MCP clients to access Monobank's open API for exchange rates, account and jar balances, and statements, as well as set webhooks, using natural language tools.

MCP server providing Polymarket weather-market bucket-transition signals for AI agents, with free city/signal inspection tools and paid signal bundles via USDC on Base using x402.

Create free, no-signup invoices from your AI assistant — the create_invoice tool returns a link that opens blankinvoicemaker.com pre-filled, ready to download as a watermark-free PDF.

Provides currency conversion using the Wise API, supporting real-time and historical rates with caching and cross-rate calculation.

Enables AI agents to discover, inspect, and pay for paid HTTP and MCP services using USDC on Solana with a self-custodial wallet.

A local MCP server that integrates ProofJSON to assess invoices before payment, providing allow/review/block decisions with confidence scores and verification capabilities.

Enables interaction with FastSpring e-commerce platform for managing orders, subscriptions, and accounts through natural language using the Model Context Protocol.

Lets AI agents discover, pay for, and call any HTTP API per request using USDC, with gasless nanopayments and no API keys or accounts needed.

An MCP server that lets your AI coding agent (Claude Code, OpenClaw, Codex, Cursor, etc.) discover and pay on-chain agents registered on ERC-8004, using Coinbase's official x402 protocol. No smart account. No bundler. No relay. Just your EOA, an HTTPS request, and an automatic 402 → sign → retry flow.

Enables AI agents to autonomously pay for Xiaohongshu note details, user notes, and wholesale pricing data using USDC micropayments on Base via x402, with automatic payment signing, retries, and configurable spending limits.

Enables AI agents to call x402-gated APIs using a central credit balance, abstracting away blockchain complexity and payment proofs. It provides tools to fetch data from payment-required endpoints, check usage balances, and simulate transaction costs.

Enables Claude to interact with the Open Finance Brasil APIs, allowing users to query accounts, balances, transactions, credit cards, PIX keys, initiate PIX payments, and view investments across supported Brazilian banks using natural language.

Enables AI agents to discover, evaluate, and purchase live data from the Macaroon Network marketplace using semantic search, metadata checks, and Bitcoin Lightning payments.

Enables AI agents to browse the giftcardshop catalog and purchase gift cards using Lightning payments, with no account or signup required.

Enables Claude to interact with a Folio business bank account for managing accounts, transactions, receipts, bookkeeping, and payments as drafts.

Connects Claude to Splitwise for natural-language access to expenses, groups, friends, and balances.

Enables AI agents to generate documents (PDF/DOCX/Factur-X) and manage electronic signatures (eIDAS/PAdES) via natural language using LayerOne's DocX and Sign APIs.