Best PKM Tools 2025: Build Your Second Brain with These Apps

Personal Knowledge Management (PKM) is the practice of capturing, organizing and connecting information in a way that makes it retrievable and useful. The "second brain" concept — popularized by Tiago Forte's book of the same name — describes an external system that remembers for you, freeing your mind for creative and analytical work.

The right PKM tool determines how useful your second brain actually becomes. This guide covers the best options for 2025, from simple note-takers to full-featured knowledge graphs.

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What Makes a Great PKM Tool?

A strong PKM system needs:

• Capture — quick, low-friction way to save ideas from anywhere
• Connect — ability to link related notes across topics
• Review — systems for surfacing old notes when relevant
• Create — turning captured notes into new work

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Top 10 PKM Tools for 2025

1. Obsidian — Best for Power Users and Privacy

Price: Free (personal); $50/year (Sync); $8/month (Publish)

Obsidian stores your notes as plain text Markdown files on your local device — no cloud dependency, no vendor lock-in. Its bidirectional linking creates a knowledge graph of connected ideas, and 1,000+ community plugins extend it for any workflow.

Key features:

• Markdown files stored locally (you own your data)
• Bidirectional links and backlinks
• Graph view visualizing knowledge connections
• Canvas for visual idea mapping
• 1,000+ community plugins (Dataview, Templater, Tasks)
• Daily notes for journaling and log-keeping
• End-to-end encrypted sync (Obsidian Sync)
• Publish as a website (Obsidian Publish)

Best for: Power users, writers, researchers and anyone who prioritizes data ownership and deep customization.

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2. Notion — Best All-in-One Workspace

Price: Free; Plus $10/month; Team $15/month

Notion combines notes, databases, wikis, project management and collaboration in a single workspace. For teams and individuals who want their knowledge base integrated with their work, Notion is the most versatile option.

Key features:

• Rich text + database hybrid
• Linked databases and relations between notes
• Views: table, board, gallery, calendar, timeline
• Notion AI for drafting and Q&A on your notes
• Real-time collaboration
• Public pages with custom domains
• Templates library for any use case

Best for: Teams and individuals who want notes integrated with project management.

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3. Roam Research — Best for Non-Linear Thinking

Price: $15/month or $165/year

Roam introduced the concept of daily notes and bidirectional links to mainstream productivity. Its block-based structure and [[Page]] linking create a web of thought that surfaces unexpected connections between ideas.

Key features:

• Daily notes as the default capture point
• Bidirectional links with block-level granularity
• Block references (embed any block anywhere)
• Graph overview of note connections
• Roam Depot for community extensions
• Sidebar for split-view working
• Query blocks for filtering content

Best for: Researchers, academics and thinkers who want maximum flexibility and don't mind a steeper learning curve.

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4. Logseq — Best Free Obsidian/Roam Alternative

Price: Free (open source)

Logseq combines Obsidian's local-file approach with Roam's daily-notes-first workflow. It's open source, stores files as plain text and offers a full outliner structure. One of the best free PKM tools available.

Key features:

• Outliner structure (hierarchical bullets)
• Bidirectional links and block references
• Daily notes for capture
• Graph view
• Queries for filtering and database-like views
• Flashcard system for spaced repetition
• PDF annotation
• Open source with active development

Best for: Users who want Roam-like functionality for free with local file storage.

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5. Tana — Best for Structured Knowledge

Price: Free (beta); pricing TBD

Tana is the newest major PKM tool, designed from scratch for 2025. Its "supertag" system lets you define typed nodes (Person, Book, Project, Concept) with properties — creating a structured knowledge graph that's more like a personal database than a note-taking app.

Key features:

• Supertags for typed, structured notes
• Inline fields and properties per note type
• Live filtering with Tana's search syntax
• AI integration for note enrichment
• Templates with automatic field population
• Daily notes with reference calendar
• Collaboration (beta)

Best for: Users who want structured, database-like note-taking with the flexibility of a PKM tool.

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6. Capacities — Best for Visual Thinkers

Price: Free (limited); Pro €10/month

Capacities uses "Objects" instead of notes — a Person, a Book, a Concept, a Project each have their own type with consistent properties. The visual interface and card-based design make knowledge exploration more visual and intuitive.

Key features:

• Object types (Book, Person, Project, etc.)
• Properties per object type
• Daily notes integration
• Visual card layout
• Bidirectional links
• Collections for curated topic overviews
• AI writing assistant

Best for: Visual thinkers who want their PKM to feel like exploring a mind map, not a file system.

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7. Readwise Reader — Best for Reading PKM

Price: $7.99/month

Readwise Reader is a read-later app and highlight manager that feeds into your PKM. Import articles, PDFs, newsletters, tweets and YouTube transcripts, highlight key passages and sync those highlights to Obsidian, Notion or Roam automatically.

Key features:

• Save articles, PDFs, newsletters and tweets
• Highlight and annotate everything
• Daily Review: spaced repetition for highlights
• Auto-sync to Obsidian, Notion, Roam, Logseq
• Mobile reading with offline support
• Email newsletter support
• YouTube transcript import

Best for: Avid readers who want reading highlights automatically flowing into their note-taking system.

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8. Mem — Best AI-Powered Note App

Price: Free; Pro $14.99/month

Mem uses AI throughout — it automatically organizes notes without folders or tags, resurfaces relevant past notes when you're writing on related topics and answers questions about your notes. It's the most AI-native PKM tool available.

Key features:

• Automatic organization (no manual tagging)
• Smart search that understands questions
• Mem X: AI that surfaces relevant past notes
• Smart suggestions while writing
• Collections for curated note groups
• Integration with email and calendar

Best for: Users who want AI to handle organization and surfacing rather than doing it manually.

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9. Bear — Best for Apple Users Who Write

Price: Free; Pro $2.99/month

Bear is the best note-taking app for the Apple ecosystem — beautiful Markdown editor, tag-based organization, wiki-links between notes and excellent sync across Mac, iPad and iPhone. Less powerful than Obsidian but far easier to use.

Key features:

• Tag-based organization (nested tags)
• Markdown with live rendering
• Wiki-links between notes
• Export to 8 formats
• X-callback-url for automation
• Focus mode
• End-to-end encrypted sync (Pro)

Best for: Apple users who want a beautiful, simple note app with linking capability.

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10. Evernote — Most Established Option

Price: Free (limited); Personal $14.99/month; Professional $17.99/month

Evernote was the original second brain app and remains a capable option, particularly for users who need web clipping, document scanning and notebook organization. Its recent pricing changes and feature additions have divided its user base.

Key features:

• Web clipper for saving articles and pages
• Document scanning with OCR
• Notebook and stack organization
• Tasks integration
• Templates library
• Integrations with Google Drive, Slack, Outlook
• Offline notebooks

Best for: Users who need web clipping, document scanning and have been using Evernote for years.

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Building a Second Brain: PARA Method

Tiago Forte's PARA method provides a universal organization structure:

• Projects: Active work with a deadline
• Areas: Ongoing responsibilities (health, finances, work)
• Resources: Topics of interest for future reference
• Archive: Inactive items from the above

This structure works in any PKM tool and provides clarity on what to capture and where to put it.

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FAQ

Obsidian vs. Notion: which is better? Obsidian for data ownership, local files and deep linking. Notion for collaboration, databases and all-in-one workspace. Many serious PKM users combine both.

What is a second brain? A "second brain" is an external system (typically digital) that captures and organizes information, freeing your biological brain for thinking rather than remembering. The term was popularized by Tiago Forte's book and course.

How long does it take to set up a PKM system? Start simple: capture daily notes for 30 days in your chosen app before adding structure. Premature organization is the biggest PKM mistake — let your patterns emerge before systematizing them.

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Conclusion

Obsidian is the most powerful PKM tool for users who value data ownership and customization. Notion is the best team option. Logseq provides Roam-like features for free. Tana represents the next evolution of structured PKM. And Readwise Reader is essential for anyone who reads heavily and wants highlights flowing into their knowledge base automatically. The best PKM tool is the one you'll actually use consistently — start simple and add complexity as you identify specific needs.

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