"Using VASP for First-Principles Materials Calculations" matching MCP servers:

Free x402 endpoint checker plus paid report and metadata tools. Remote MCP server for agents. Written by AI named Nock, not a human.

Pay-per-call USDC payment proxy for AI agents. Issue scoped Pay Tokens with hard spending caps and auto-journal every charge to freee / Money Forward / QuickBooks.

Provides a three-layer payment firewall for AI agents, enabling identity verification, risk screening, and execution authorization with on-chain policy enforcement for secure and auditable transactions.

The first commercial implementation of HTTP 402 Payment Required for creator content monetization. AI agents pay $0.0025 per content pull from paywalled creator libraries. Creators get paid automatically.

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.

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.

MCP server for real FDM 3D-printing slicing, quoting, and design-for-manufacturability analysis via the FabTally API, supporting 12 printer profiles and 12 materials. Includes free discovery/printability tools and paid slice/quote/orientation tools settled via x402 (USDC on Base).

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

A Model Context Protocol server that enables interaction with Monobank API, providing tools for currency exchange rates, client info, and account statements.

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

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.

Non-custodial USDC <-> bank for AI agents. Free quotes; $0.05 USDC per session via x402; 1% commission itemised in every quote. Own funds only. PT + EU/EEA (not UK). 18+.

Payment firewall for AI agents: a signed, independently verifiable verdict on every money-moving action. Blocks wrong/lookalike payee, over-cap, and duplicate-invoice (BEC) fraud before money moves — anyone can verify a verdict against the public JWKS. Free, local-first, non-custodial.

MCP server for JazzCash mobile wallet and payments (Pakistan). Supports wallet payments, mobile account payments, vouchers, refunds, and balance inquiries.

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.

LFWin Payment MCP Server is a payment capability service for AI Agents. Adhering to the standard MCP protocol, it exposes capabilities including creating payment orders, checking payment status, initiating refunds and querying refund status for Cursor, Cline, Claude Desktop, enterprise intelligent assistants and self-developed Agent applications.

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.