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

Enables free web searches using DuckDuckGo results without requiring API keys or authentication, returning structured titles, URLs, and descriptions with a configurable result limit.

Network diagnostics tool for AI agents that provides DNS lookup, IP geolocation, SSL certificate inspection, WHOIS queries, and HTTP latency testing.

Enables deploying pre-built AI agent blueprints for RFx procurement and employee onboarding, with no signup or API key required.

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.

An MCP server that gives your agent a persistent project brain: vision, architecture decisions, conventions, roadmaps, and automatic session handoff.

Provides an OpenAI-compatible gateway to the MiMo (Xiaomi) model series, with native MCP server tools for web search and visual analysis.

Validates submitted fields against required field names and returns structured validation results. It is a read-only, deterministic tool that does not call external APIs or modify data.

Free DEX aggregator API that returns executable swap calldata across 46 EVM chains. No API key required. Single GET request returns ready-to-sign transactions for any token pair.

Enables AI agents to dynamically spawn, route to, and manage ephemeral containerized sandboxes on Kubernetes without requiring Custom Resource Definitions or cluster-level operators.

MCP server for managing a home network via a UniFi Dream Machine, enabling device lookup, tagging, and blocking/unblocking of clients through natural language.

Provides free public investment research tools including stock quotes, SEC filings, macroeconomic indicators, and clinical trial searches without requiring API keys.

Enables querying Context7 V2 documentation through resolve-library-id and query-docs tools, alternating between two API keys and retrying when a key is blocked.

Self-hosted personal knowledge graph for Claude that persists across sessions, devices, and tools. Built on Neo4j with local semantic embeddings; OAuth 2.1 lets Claude Code, Claude Desktop, and claude.ai web all hit the same graph.

Multi-agent swarm orchestrator for AI workflows. Exposes blackboard read/write, agent dispatch, permission gating (AuthGuardian), token budget enforcement (FederatedBudget), and audit log tools over MCP. Supports 14 AI framework adapters including LangChain, AutoGen, CrewAI, Codex, and A2A — mix any frameworks in one swarm with race-condition-safe shared state.(Traffic light for agents)

Provides read-only access to UniFi Network consoles for sites, devices, clients, vouchers, networks, Wi-Fi, and firewall configuration, with optional opt-in tools for controlled write operations and legacy controller support.

MCP server providing typed, safety-gated access to UniFi Network consoles via the official API, enabling management of devices, clients, networks, WiFi, firewall policies, and more.

Exposes the UniFi Network Integration API as tools for managing sites, devices, clients, networks, WiFi, firewalls, ACLs, switching, DNS policies, hotspot vouchers, VPNs, and more.

Local-first memory for Claude Code and any MCP client: hybrid vector + keyword search and a bi-temporal knowledge graph in one SQLite file. Local embeddings, no API key, $0/token.

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.

Free Polish VAT invoice generation MCP server with PDF output and preview. No API key required.