Logseq

Logseq is an open-source outliner designed for knowledge workers building digital gardens and second brains. It works directly on your local Markdown files, giving you complete control and portability. The platform excels at bi-directional linking, backlinks, and a visual graph view that shows how your ideas connect—making it perfect for researchers, academics, and writers exploring complex knowledge systems.\n\nUnlike Roam Research's closed-source SaaS model, Logseq is free, open source, and stores everything in plain-text Markdown. This means you can edit notes in any text editor and keep your data forever. The active community has built extensive plugins and themes, and Logseq Sync is optional (paid feature).