"Tools and methods for plotting graphs without an API key" matching MCP servers:

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.

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.

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.

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.

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

Connects MCP clients to a telephony account so users can manage phone numbers, SIP accounts, routing, SMS, calls, and billing in plain language. It exposes search, schema lookup, and execute tools to run permitted API operations, with confirmation required for paid or destructive actions.

Enables AI agents to create and manage contract-guarded USDC wallets on Base with enforceable per-payment, daily, and monthly caps, vendor allowlists, escalation thresholds, and freeze controls. It provides read-only policy checks plus unsigned transaction proposals for payments, funding, vendor management, wallet creation, and module deployment without holding keys or broadcasting.

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.

Enables AI agents to read and change jobs, job status, customers, quotes with line items, invoices, quote and invoice email, payments, and Scheduler bookings in an account by reusing the user's own signed-in Chrome session, with no official API keys needed. Ships read-only hints and confirmation prompts for tools that reach other people, and can be run over stdio or streamable HTTP.

10 MCP servers so agents can work in Korea: Naver Smart Store, Coupang, Cafe24, public data (business status, holidays, addresses), HWP files, KakaoTalk, Popbill e-tax invoices & 알림톡, Toss Payments, Japan→Korea sourcing, tax calendar — with human approval on every write. npm @appmonster/mcp-*.

Enables AI agents and scripts to manage bookings, provider assignment, rescheduling, cancellations, customers, quotes, invoices, and dashboard data through a self-hosted API and MCP interface using your own Chrome session.

Enables AI agents to integrate Midtrans payments by providing comprehensive documentation, API references, and code examples for 15+ payment methods across 5 languages. Includes tools for generating charge requests, webhook handlers, and searching documentation without requiring API keys.