"Free Graph and Network Visualization Tools (No API Key Required)" matching MCP servers:

MCP stdio server that exposes 95 headless it-tools utilities (crypto, encoding, converters, generators, text, math, and more) through three routing tools (categories, list, execute), with flat JSON schemas, worked examples, and deterministic seeded execution designed for small router models.

Provides 14+ character-level text analysis tools that give LLMs the ability to accurately count letters, analyze individual characters, and work with text at the character level—overcoming tokenization limitations.

Enables AI assistants to search YouTube, fetch transcripts, and get AI summaries of videos without API keys.

An MCP server that enables users to read, search, and analyze PDF documents. It provides tools for extracting text, viewing metadata, searching content with context, and generating word statistics.

Enables sentiment analysis of text blocks using the Api Ninjas API, returning sentiment scores and overall sentiment classification for up to 2000 characters of text.

A TypeScript-based MCP server that implements a simple notes system, providing resources for accessing notes via URIs, tools for creating notes, and prompts for generating summaries.

The local PDF workflow for Claude Desktop and MCP hosts: fill, sign, merge, split, extract, and analyze PDFs without sending files to a web app.

Provides a suite of regex and text processing tools for AI agents, including pattern testing, extraction, and replacement with capture group support. It also enables various text transformations like case conversion, line sorting, and deduplication through the Model Context Protocol.

An MCP server that provides developer knowledge and utility tools including local documentation search, text summarization, safe arithmetic calculation, unit conversion, and knowledge-base resources.

An AI-powered study assistant that generates quizzes, flashcards, summaries, and concept explanations from study materials using the Model Context Protocol.

Algorithmic text and NLP analysis server providing sentiment, readability, keyword extraction, language detection, stats, and more via REST and MCP.

MCP server for koreafilings.com — AI-summarized Korean DART (전자공시) corporate disclosures, paid per call in USDC via the x402 protocol on Base. Tools: get_pricing (free), get_disclosure_summary (0.005 USDC).

Enables exploring Steam store reviews and community discussion threads with server-side filtering, temporal analysis, and metadata context for understanding player sentiment and feedback beyond store page noise.

A modular production-ready system that provides specialized agents for math, research, weather, and summarization tasks through a unified MCP toolbox with smart supervisor capabilities.

Stdio MCP server over the Briefing Service REST API: hourly LLM-ranked news briefings (AI, frontier labs, markets, sports, world) as structured JSON, rendered e-ink pages and a free provenance dump. Six read-only HTTPS tools, no shell, no secrets required; Dockerfile and glama.json in the repo root.

Provides various AI capabilities through DeepInfra's OpenAI-compatible API including image generation, text processing, embeddings, speech recognition, object detection, and classification tasks. Enables users to access multiple AI models for diverse tasks like generating images from prompts, transcribing audio, analyzing text sentiment, and performing computer vision operations.

This TypeScript-based MCP server allows users to manage and interact with a note system through Model Context Protocol, enabling note creation and summarization with URIs and metadata.

Enables access to Humanizer APIs for text humanization with multiple models including basic, easy-use, and multi-language support. Requires API key authentication.

Provides access to Open Ai21 API services including chatbots (GPT-3.5, Claude 3, Llama 3), text-to-image generation, image background removal, text-to-speech, question answering, and text summarization capabilities.

Provides AI agents with comprehensive document parsing capabilities including PDF text extraction, OCR, HTML-to-markdown conversion, table extraction, and summarization, optimized for agent workflows.