"Services or tools available for free without requiring an API key" matching MCP servers:

A comprehensive suite of HTTP and API testing tools that enables AI agents to perform requests, check endpoint health, and decode JWTs. It also provides utilities for URL parsing and detailed security analysis of HTTP response headers.

Code Mode MCP server for the OVH API. Two tools (search + execute) give LLMs access to all OVH endpoints via sandboxed JavaScript.

Webhook management and testing tools for AI agents. Provides tools for sending, validating, generating, and debugging webhooks.

An MCP server that makes backend API requests and packages request+response pairs as evidence to prove an endpoint works.

A lightweight, local-first MCP server for executing HTTP requests and managing API collections and environments without cloud dependencies. It enables testing APIs, handling authentication, and importing OpenAPI specifications directly within MCP-compatible workflows.

A Model Context Protocol server that creates tools from API configurations defined in YAML files, allowing easy integration of external APIs into an MCP ecosystem without coding.

Enables interaction with Nullplatform's API endpoints for managing deployments, scopes, services, and other cloud resources through natural language using the official OpenAPI specification.

A CDP-native MCP server that lets AI agents drive a real Chrome browser with deep network/console inspection, robust page interaction, and the ability to reverse-engineer a site's API flow into runnable code with dependency chaining and replay verification.

Enables agents to invoke any REST or SOAP service by sending a normalized payload, with support for API key, Basic, Bearer, and OAuth2 auth. Connectors can be registered once and reused by name.

Converts SOAP WSDL services into a REST interface and provides MCP tools to describe, invoke, and manage SOAP operations with caching and WS-Security support.

Exposes REST API endpoints defined in an OpenAPI Specification as MCP tools, allowing AI models to call them via the ModelContext Protocol.

Provides a standardized MCP interface for interacting with HTTP tools and services, enabling unified API access and management.

Enables AI assistants like Claude to interact with any REST API through typed, validated MCP tools. Provides a pattern to wrap REST APIs as MCP servers.

A Swagger/OpenAPI query tool for MCP clients like Cursor, enabling AI assistants to browse, search, and retrieve detailed API type information.

Enables LLMs to make arbitrary HTTP API requests with any method and full control over headers, query parameters, and body.

Enables read-only exploration of YApi projects, categories, and interface docs, and deterministic TypeScript/JavaScript API request function and type generation through a preview-then-apply workflow.

Starter scaffold for a workshop to build an MCP API testing server, intended to be extended through incremental steps.

Enables interaction with Users and Products through a CRUD service REST API, providing tools for listing, creating, reading, updating, and deleting records via HTTP transport.

MCP server for making API calls with authentication support. Allows configuring multiple API endpoints and performing GET, POST, PUT, DELETE requests, including form data and file uploads.

Converts any REST API endpoints into MCP tools, enabling AI clients like Cursor and Claude Desktop to call internal services directly.