"Free APIs and services without commercial fees" matching MCP servers:

Free service management tools — playbooks, benchmarks, and instant service health analysis. DigitalCore MCP gives you free access to service management expertise directly in your AI assistant. Run a Service Reality Check to score your service health in 60 seconds. Access strategy playbooks for ser

MCP server for the Synapse ecosystem that exposes the Synapse Memory API, Browser Proxy, and SSH Proxy as MCP tools, enabling multi-tenant, stateful interactions via stdio or HTTP/SSE.

Connects AI assistants to your Limitless AI lifelog data, enabling them to search, retrieve, and analyze your recorded conversations and daily activities from your Limitless pendant.

Enables AI agents to store and retrieve project context, bugs, decisions, and session logs by reading and appending markdown files in a local Obsidian vault, without requiring any cloud services.

Enables Claude and ChatGPT to share a single study-progress database for interview prep, coursework, and spaced repetition, with per-user data isolation and server-side SM-2 scheduling for due reviews and study plans.

TheWeave is a markdown-native memory architecture for Claude and any MCP-aware agent. Your agent's memory lives as plain .md files you own: a 5-verb MCP core over the vault, query-driven PageRank retrieval, bi-temporal facts (valid_from / valid_until), and a persona-as-vault model. No database and no embeddings server. The files are the memory, inspectable in your editor and versionable in git.

Enables local MCP clients to list, read, write, and search notes in an Obsidian vault via an HTTP server running inside Obsidian.

Privacy-first local document search using semantic search. Runs entirely on your machine with no cloud services, supporting PDF, DOCX, TXT, and Markdown files.

Enables any LLM to process arbitrarily long contexts through recursive decomposition, without requiring external LLM APIs.

Exposes tools to ingest FigJam boards, retrieve context summaries, and answer free-form questions about the board content.

Enables an LLM to autonomously maintain a Markdown-based wiki with YAML frontmatter, using hybrid BM25 and local CPU vector search for fully offline retrieval without external APIs or databases.

Enables Claude Desktop and compatible agents to search, read, add, update, and delete a locally stored, user-curated memory using hybrid retrieval with reranking and Qdrant. All processing runs locally without cloud services or API keys.

A local MCP server that helps you maintain a personal Japanese learning knowledge base, including vocabulary, confusion relations, mistakes, and spaced-repetition reviews. It provides tools and prompts for managing and reviewing your Japanese learning data without calling external LLM APIs.

MCP bridge for PDF Content Search — full-text PDF search with Apple Vision OCR across thousands of documents in under a second from Claude, Cursor, or any MCP client. Advanced filters (date, category, sender, amount), wildcards, boolean operators. Bridge open-source (MIT), PDF Content Search app is commercial with free iOS+Android companion scanner apps.

Provides local-first durable memory and session continuity for AI coding agents over MCP, enabling context across restarts without cloud services or telemetry.

Enables AI coding agents to persist, share, and retrieve project context locally via plain-text files, with support for capturing, packing, searching, and importing transcripts without external services.

Free, open MCP server for The Urantia Papers — full-text and semantic search across 197 papers, 14,500+ paragraphs, and 4,400+ named entities.

File-backed Memory MCP Server for multi-agent coordination, enabling AI coding agents to persistently store and search memories using JSON files without external services.

Provides persistent, searchable memory for Claude Code using local SQLite, semantic embeddings, and full-text search, enabling Claude to recall and retrieve context across sessions and projects without external services.

Enterprise MCP server that exposes multiple MySQL databases to AI services through one endpoint, with API-key auth, per-key database scoping, a layered SQL guard, and a markdown schema-knowledge graph.