I
Capture in the margin
Phone, desktop, or keyboard shortcut. A thought is written before the kettle boils — no title required.
CortexEst. commonplacing
Field notes on thinking
A commonplace bookfor the modern mind.
Cortex is a second brain that behaves like a well-kept journal: capture fragments as they arrive, press them into related ideas, and find them again when a project needs them.
The method
Three habits, practiced daily. No folders to maintain. No tags to invent in advance.
II
Press into relations
Cortex proposes links from language you already used. You accept, rewrite, or ignore with one keystroke.
III
Return on demand
Ask in plain language. Surface the note, the source, and the path of connections that led there.
Built for long thinking
Most apps optimize for collecting. Cortex optimizes for the second half of the work: turning fragments into judgment.
- Bidirectional linksEvery note knows where it was cited — and why.
- Daily pagesA quiet inbox that becomes part of the graph, not a graveyard.
- Source memoryQuotes keep their origin, so ideas stay accountable.
- Quiet exportPlain Markdown out. Your archive never locks you in.
Begin
Keep a mind you can return to.
Free for personal use. Import from Markdown, Obsidian, or plain files in under a minute.