"How to use a search engine" matching MCP servers:

Pay-per-use semantic web search for AI agents. Powered by SearxNG, agents pay in sats via Lightning Network micropayments — no API keys required.

A standard MCP server for discovering AI agents and negotiating signed skill contracts. Buyer-seller payments are settled directly outside the platform; Agent Economy Engine collects only a platform fee after both parties attest completion.

A pre-payment safety gate for x402 that screens payment metadata for PII, enforces spending policies, and detects replay attacks before signing.

The first commercial implementation of HTTP 402 Payment Required for creator content. AI agents discover music, video, and text catalogs as pre-indexed Pockets (list_pockets, search_pockets — free, no key) and pull licensed content per-use through a 402 paywall. Tiered per-pull pricing by content type; 85% of every pull pays the rights holder instantly, with attribution and an audit trail.

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.

A paid MCP server that lets AI agents send SMS messages to US phone numbers via x402 micropayments, with automatic compliance and opt-out handling.

Enables AI agents to discover and pay for x402-gated HTTP APIs, handling 402 Payment Required flows with local signing. Supports EVM and Solana with non-custodial wallet management.

Keyless crypto payments for AI agents. One MCP call turns any wallet address into a non-custodial crypto payment link or tip jar, no API key and no account, with funds settling straight to your wallet at a 0% platform fee (USDC/USDT, BTC, LTC, DASH, DOGE, ZCASH).

MCP server for the Gravv payments API that lets AI assistants onboard customers, run KYC, open accounts, move money, issue cards, and exchange currency, with built-in documentation search and safety confirmations for money-moving operations.

A local, read-only stdio MCP server that lets a Grok Build CLI agent check how much of its weekly SuperGrok / Grok Build usage pool is left, when the period resets, and its Extra Usage cap via tools like get_budget. It reads the existing grok login session and returns per-product figures as JSON, mirroring the TUI /usage screen, so agents can pause before expensive work when quota runs low.

A read-only MCP server for the open-banking.io PSD2 API that lets AI agents query personal bank balances and transactions via natural language, with zero-knowledge encryption ensuring all sensitive data is decrypted in-process and never exposed to third parties.

Official Dodo Payments MCP servers - dodopayments-api for live payments, subscriptions, customers, products, refunds, license keys, and usage-based billing (browser OAuth, no API key needed) and dodo-knowledge for semantic search over Dodo Payments documentation.

Enables AI agents to search marketplace listings, place escrow-protected purchases paid in Nano, track orders, and retrieve signed receipts.

x402-trust gives AI agents a "check before you pay" layer for the x402 ecosystem.

Unified gateway for ISO 20022 message families, providing meta-tools to search, describe, validate, generate, and parse financial messages.

A template for building MCP servers with a built-in paywall gate that offers free local execution and premium server-side execution via Stripe and x402 payment lanes.

Enables AI agents to draft AP-style press releases from a product URL and publish them to a public newsroom page, or distribute them across a newswire to hundreds of news, TV and radio sites, with status tracking for wire orders. Paid calls are settled per request in USDC on Base via x402 from the user's own wallet, defaulting to quote-only mode with spend caps and confirmation tokens.

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 AI agents to verify email addresses with catch-all detection, search existing contacts by company domain, and, when no API key is present, provision a human-approved subscription and retrieve the key after payment.

Enables running a local MCP server for Poland's KSeF (Krajowy System e-Faktur) e-invoicing system, so invoice data stays on the user's own machine rather than passing through an intermediary service. It currently exposes only a diagnostic server_info tool, with invoice search and retrieval tools still to come.