Capacities

Mem

Mem is an AI note-taking and personal knowledge management app that captures notes and automatically organizes and links them, aiming to reduce the manual filing and tagging typical of traditional note apps. Version Mem 2.0, released in 2026, added faster performance and deeper AI features described as a 'thought partner' for surfacing relevant past notes during writing or planning. The app is available as native apps for Mac, Windows and iOS as well as a web app, with offline editing that syncs once back online. A free tier covers core note-taking with capped monthly AI usage, while a paid Pro tier raises those limits, and a Teams plan adds shared workspaces for collaboration.

Supernotes

Supernotes is a note-taking app built around individual notecards rather than long linear documents. Each card can hold rich content such as tables, equations, images, and checklists, and cards can be linked together and viewed as a 2D or 3D graph to visualize how ideas connect. The platform supports hierarchical organization with filters and search, real-time collaboration and commenting, and multi-device sync across web, desktop, and mobile apps. AI-powered assistance helps with tasks like typo detection and organizing ideas, and Supernotes is positioned for a broad range of users including students, developers, writers, researchers, and other professionals who think in small, connected chunks rather than long documents.

Roam Research

Roam Research is a web‑based note‑taking platform built around bi‑directional links and a graph view, allowing users to create a web of interconnected ideas. Its daily notes page encourages a habit of capturing thoughts as they happen, while the query language lets you retrieve information across the entire knowledge base. Designed for researchers, writers, and knowledge workers, Roam supports markdown, collaborative editing, and real‑time syncing across devices. The platform’s open API enables custom integrations and automation, extending its capabilities beyond personal use.

Obsidian

Obsidian is a note-taking and personal knowledge management app built around plain markdown files stored locally on your device. Rather than a rigid folder hierarchy, Obsidian encourages a networked structure through bidirectional links, backlinks, and an interactive graph view that visualizes how notes connect. Because notes are just markdown files on disk, Obsidian is fast, works fully offline, and keeps your data portable - there is no proprietary lock-in. A large community plugin ecosystem extends the core app with everything from spaced-repetition flashcards to kanban boards and calendar views. Obsidian Sync and Obsidian Publish are optional paid add-ons for cross-device syncing and publishing notes as a website, but the core app is free for personal use.

Foam

Foam is a free, open-source note-taking application that uses a graph database to store notes as a network of interconnected ideas. It's designed to help users create a knowledge graph, where each note is a node that can be linked to other notes, creating a web of relationships between ideas.

Tana

Tana is a networked note‑taking and knowledge‑management platform that lets users organize information as data using a powerful supertag system. Instead of flat documents, each note can be tagged, linked, and queried, turning personal knowledge into a searchable graph. The service runs in the cloud, offering real‑time collaboration, automatic syncing, and integrations that let you bring data from other tools into your Tana workspace. Its design focuses on turning ideas into actionable, structured information without forcing a rigid hierarchy.