Alternatives to Second Brain for Mac and Windows

Constella is a shared infinite-canvas memory layer that gives Claude Code, Codex and ChatGPT the same context across your notes, messages

MyMemo AI is an AI second brain that saves articles, videos, PDFs and voice memos as searchable notes with sourced answers.

OttO is a local-first MCP memory server and knowledge graph that gives Claude Code and Cursor persistent agent memory

MindMarks is a browser extension that saves and searches your ChatGPT, Gemini, and Claude chats from one dashboard.

Proactive AI second brain that organizes saved pages, PDFs, videos and tweets into guided learning Flows.

Kortex is an AI second brain and writing workspace that turns your captured notes and highlights into finished drafts.

LLM Wiki auto-compiles your raw PDFs, notes and transcripts into a self-hosted, LLM-maintained markdown wiki

mymind is a private AI memory app that auto-organizes your bookmarks, notes and images so you remember everything and organize nothing.

Glasp is a social web and PDF highlighter that turns your highlights into an AI memory you can chat with.

Liminary is Chrome-extension research memory that captures what you read and grounds client deliverables in your own sources.

Mem is an AI knowledge base that organizes what you capture and has an Agent that checks in when something needs you.

Heptabase is a visual knowledge base where an AI Tutor turns your PDFs and YouTube videos into guided study courses.

Self-hosted AI workspace with AI search over your own docs, wikis, and databases

remio is a local-first AI agent that turns your files, meetings, and research into finished decks, spreadsheets, and reports.

Ophel adds a real-time smart outline, chat folders, and a prompt library to 15 AI chat platforms — free and open source.

Twigg is a stateful LLM API that stores conversation context server-side and routes each request to Anthropic, OpenAI, Google, xAI,

Open-source knowledge graph builder that compiles your files into a provenance-tracked LLM wiki you own locally.

Knowing® is a v0.2 preview tree outliner that runs expand, summarize, and autocomplete AI actions on individual outline nodes rather than in a chat thread.

MindPocket: open-source, self-hosted AI bookmark manager that summarizes, tags, and answers questions about your saved links.

illumi is a browser-based AI visual workspace where 30+ models share one context canvas and your reasoning stays attached to the output.

Free Obsidian plugin that surfaces related notes and passages beside your current note using local embeddings.

Khoj is an open-source AI second brain that turns your documents and the web into private, queryable agents.

Messync is a grounded research workspace that cross-examines a client project's decks, spreadsheets, and interviews with citations you can

Free open-source Chrome and Firefox extension that saves ChatGPT, Claude, Perplexity and Phind threads as markdown files in one click.

A local-first markdown knowledge base scaffolded with six named AI specialist roles you point any LLM client at.

Pieces builds a searchable on-device memory layer from everything you do on your desktop, then pipes it into your AI assistants via MCP.

Open-source Markdown note-taking on Mac, iPhone and iPad, with backlinks, daily notes, an optional bring-your-own-key AI layer and an MCP server for Claude and

Screenpipe records your screen and audio locally, turning your computer history into AI memory your agents can search.

ScreenMind builds a local, searchable AI screen memory with on-device Gemma 4 vision analysis.

Fabric CLI brings AI semantic search and persistent agent memory to your terminal.