Overview

Obsidian is a powerful, free note-taking and personal knowledge management application that helps you organize your thoughts and build an interconnected second brain on your local device. Positioned as 'the free and flexible app for your private thoughts,' Obsidian emphasizes complete privacy through local-first storage, ensuring your data never leaves your device unless you choose to sync it. The platform's strength lies in its extensive customization capabilities, with a vibrant community that has developed over 150,000 active users using AI-enhanced plugins as of October 2025. Popular AI plugins like Smart Connections and CoPilot offer semantic search and AI-assisted editing, Khoj acts as a personal AI assistant integrating with local and online LLMs, and Smart Second Brain enables chatting with your notes using retrieval-augmented generation (RAG). These plugins support OpenAI GPT, Anthropic Claude, and local AI models, transforming Obsidian into an AI-powered knowledge management powerhouse. Beyond AI, Obsidian's core features include linking notes to create knowledge networks, graph view for visualizing relationships, infinite canvas for brainstorming, and open file formats (Markdown) ensuring data ownership and longevity. With thousands of community plugins and themes, optional end-to-end encrypted sync, and the ability to publish notes as public wikis, Obsidian serves knowledge workers, researchers, students, and teams who want privacy, flexibility, and AI-enhanced capabilities without vendor lock-in.

Pricing: Free (optional Sync $4-5/mo, Publish $8-10/mo, Commercial $50/user/year)

Minimum macOS: 10.13 (High Sierra)

Architecture: Apple Silicon, Intel

Key Features

• Completely free with no feature limits or account required
• Privacy-first: all data stored locally on your device
• 150,000+ users using AI-enhanced plugins (as of October 2025)
• Smart Connections: semantic search and note discovery (free, works offline)
• CoPilot: AI-assisted editing and content refinement
• Khoj: personal AI assistant with local and online LLM integration
• Smart Second Brain: chat with notes using RAG pipeline
• AI model support: OpenAI GPT, Anthropic Claude, local models
• Bidirectional links to create knowledge networks
• Graph view to visualize note relationships and patterns
• Infinite canvas for visual brainstorming and diagramming
• Markdown-based with open file formats you own forever
• 1000+ community plugins for endless customization
• Community themes for personalized appearance
• Optional Sync: end-to-end encryption and version history ($4-5/mo)
• Optional Publish: convert notes to public wikis ($8-10/mo)
• Daily notes and templates for journaling
• Advanced search and filtering
• Tag management and organization
• Cross-platform: macOS, Windows, Linux, iOS, Android
• Mobile apps for on-the-go note-taking
• Hotkeys and workspace customization
• Commercial license for business use ($50/user/year)
• No vendor lock-in with plain-text Markdown files

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