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

Provides 13 offline SEO and marketing tools to any MCP client, covering ad metric calculators, text and heading analysis, keyword density, and generators for meta tags, Open Graph, hreflang, schema markup, XML sitemaps, and robots.txt. Everything runs locally with no account, API key, or network calls.

Human-in-the-loop approval: a person approves the exact AI action with a passkey, and any service can check the signed approval offline.

Enables AI agents to query OpenRouter model information including prices, ELO rankings, context, and perform comparisons.

A Model Context Protocol server that provides semantic search and intelligent access to a comprehensive list of free services and tools for developers.

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.

Scans code for exposed secrets, API keys, tokens, and credentials across 69 patterns covering cloud services, AI platforms, payment providers, authentication services, and databases.

Enables Tavily and Firecrawl MCP servers to operate with multiple API keys, automatically rotating to backup keys on quota exhaustion, rate limits, or invalid keys, while rewriting API endpoints to the local proxy.

Free and open-source MCP server for managing n8n workflows, executions, and tags via n8n's API. Enables workflow creation, activation, debugging, and deletion from any MCP client.

MCP Server for Git operations, agent templates, and project utilities.

Enables Claude to connect to Figma without a paid plan, offering auto-connect and 100+ tools for document manipulation, design system sync, and code-to-Figma conversion.

This MCP server gives an AI coding host controlled, client-agnostic access to a local machine's developer capabilities: transactional file edits, shell and PTY execution, Git and project inspection, language-server operations, isolated browser automation, Windows UI automation, VS Code state, durable jobs, and checkpoints, all bounded by filesystem root allowlisting and resource admission controls. It speaks standard MCP over stdio, Streamable HTTP, and legacy HTTP+SSE, and can also run headless as a long-lived job runner without any hosted model vendor.

Enables delegating bounded execution loops—such as failing test suites, large CI logs, build/diagnose/fix/rerun cycles, and routine repo exploration—to OpenCode, which inspects and iterates on the raw output internally. Returns only a compact structured result to the primary model, with inspect and fix modes and an escalation flag when a primary-model decision is required.

Full-stack utility API with 337+ tools including AI chat, web scraping, weather, finance, SEO, crypto, colors, readability, DNS, and more — all through a single MCP server. Pay-as-you-go credits, no API keys needed.

Offers 29 free tools for text processing, AI-powered generation, SEO optimization, utilities, cron tasks, file processing, and ideas management, all without requiring an API key.

A dual-transport MCP server enabling anonymous free web search via Parallel (default) or Exa (backup), with no API keys or DSH dependency, for Claude Code, Codex, and any MCP client.

A reference MCP server that connects any MCP client to a free cloud database, supporting 15 database engines with unified tools for querying, storing, listing tables, and annotating tables.

A local MCP server that enables AI applications like Claude Desktop to securely access and work with Obsidian vaults, providing capabilities for reading notes, executing templates, and performing semantic searches.

MCP-ORTools integrates Google's OR-Tools constraint programming solver with Large Language Models through the MCP, enabling AI models to: Submit and validate constraint models Set model parameters Solve constraint satisfaction and optimization problems Retrieve and analyze solution

Search and pull 620+ React and Tailwind sections into your project over MCP.

MCP server for Cursor IDE offering tools for Human Design chart analysis, partner matching, n8n workflow management, and utility functions like UUID generation and calculation.

Free Industry 4.0 / IIoT tools, no API key or account: lint MQTT Sparkplug B topics, check a Unified Namespace (UNS) for naming and hierarchy problems, and run an industrial AI-readiness diagnostic for manufacturing digital transformation and smart-factory projects. Works in Claude Code, Codex and any MCP client.

MCP server that exposes tools to route natural language queries to typed IDs, describe catalog entries, and list repository verification commands for the m-dev-tools organization.

Enables AI assistants to keep Rojo serving and auto-connected for Roblox Studio projects and to import FBX, OBJ, GLB, or GLTF models through Studio's own 3D Importer on Windows.

Enables validating JSON/JSONC, getting/setting values with jq-like paths, pretty-printing or minifying, validating against Ajv JSON Schema, and diffing local files or inline strings without network calls.

Enables AI agents to format SQL, explain queries in plain English, analyze schemas, build queries from natural language, and generate migrations, all without requiring a database connection.

Enables AI agents to pay per call for live package-safety and GitHub merge-readiness trust signals via the x402 protocol.

Stop letting your agent guess at APIs. Ask the code you actually installed. installed-api is a Claude Code plugin (an MCP server, Python standard library only) that answers "what's the signature of X?", "does Y take that argument?" and "which version do we have?" from the packages installed in this project: your .venv, your node_modules.

Enables AI agents to execute HTTP/REST/GraphQL requests against any endpoint, including private VPN hosts and local services, while logging untruncated headers, request bodies, and raw responses into a local SQLite audit history. Agents can then search that history by keyword, date, method, or status, retrieve full details by ID, and export everything to JSON.

Enables AI models to interact with IBM FileNet Content Manager for document management, folder operations, metadata handling, search, and content extraction through a standardized interface.

Exposes AWS Palace finite-element electromagnetic simulation as a set of JSON-in/JSON-out tools, so an agent can build geometry and meshes, generate and lint configs, estimate cost, guard and launch runs, and read back S-parameters, eigenmodes, Q and energy results. Results return as JSON text plus structured content over a dependency-free stdio JSON-RPC connection.