"Web search tools and methods that don't require API keys" 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.

Enables agents to call paid utilities for DNS/SSL checks, site status, summarization, keyphrase extraction, decision advice, data cleanup, claim verification, and grounding via per-call USDC payments over x402, with free discovery tools and no signup or API key.

Provides current weather conditions and 7-day forecasts for any location worldwide, covering temperature, humidity, wind, and precipitation, with pay-per-call micropayments via x402.

MCP server for Brazilian data lookups (Pix codes, CEP, CNPJ) and web rendering tasks (Markdown, screenshots, PDFs) via a paid HTTP API with x402 billing.

Per-customer API usage analytics and billing exports for small B2B APIs. Agents can sign up, get ingest snippets and read usage by customer, endpoint and plan.

MCP server for deterministic financial transactions, providing tools to fetch account balances, check blocked PIX keys, and execute atomic PIX transfers with integer-cent precision.

MCP Server for the LINE Shopping API, enabling AI agents and tools to interact with LINE Shopping data and operations via the Model Context Protocol.

A comprehensive Model Context Protocol (MCP) server that provides complete access to the Recharge Storefront API endpoints. Enables AI assistants to manage subscriptions, customers, orders, and billing through a standardized interface.

Enables AI agents to convert PDFs and images into validated, structured JSON for invoices, receipts, contracts, and resumes, or into any caller-supplied JSON Schema, through five extraction tools. Each tool call pays per use in USDC over x402 from a wallet the caller supplies, with no signup or API key required.

MCP server for decoding and inspecting x402 payment headers and requests. Remote endpoint: https://lumenworks-x402-decoder.onrender.com/mcp

A Model Context Protocol (MCP) server that provides testing and debugging tools for Stripe integrations, including test clock management, customer and product management, and subscription testing.

Enables AI agents to use pay-per-call web-to-Markdown, structured extraction, crawling, Base token and wallet data, FX rates, and crypto alert tools via USDC payments on Base.

An MCP server for Nexi POS payment operations, enabling creation of purchases and refunds, polling payment states, confirming transactions, and recovering unconfirmed transactions.

Discover audio and LLM services, compare seven voices, and check prices for free. Generate speech, transcribe audio and request LLM text with optional capped USDC payments on Base; voice-cloning requirements are also available.

Credit and payments for AI agent developers — over MCP. No crypto required

Open-source registry of structured API specs for African providers: payments (Wave, Paycard, ...), SMS and WhatsApp (Africa's Talking, Infobip, ...), identity, delivery and speech. AI agents read the real endpoints, parameters and gotchas and write the integration. Each capability is marked verified (tested against the live API) or ready (written from the docs, not yet tested).

Lets agents discover and health-check a directory of live x402 pay-per-call endpoints, probe an individual URL with one unpaid request to see whether it returns a payment challenge and at what price, and read on-chain settlement demand for crawled sellers. It also serves reproducible, solver-verified sudoku puzzles and the pricing, network, and payment details of the studio's paid pay-per-call routes.

Marketplace of MCP servers and APIs that agents pay for per call in USDC over x402 on Base; connect anonymously, pay only when you call

Enables AI agents to access real-time financial data, news, and web reading through a single MCP endpoint with zero installation.

Free MCP/API that scores a planned spend and returns approve, ask_human, or block so agents don't burn money by mistake.