Capture without ceremony
A note starts as a fragment — a quote, a hunch, half a sentence. Drop it in the soil; no folder decisions required.
Personal knowledge management, minus the management
Ideas grow when they’re connected.
Cortex turns your notes into a second brain: a living network where every thought feeds the next. Capture fragments, link them loosely, and harvest fully-grown ideas later.
Joined by 41,203 gardeners of thought
The lifecycle of a thought
How a note becomes knowledge
Link it to what you know
Each connection is a root. Link the fragment to a book, a person, a project — and it starts drawing nutrients from all three.
Resurface in context
While you write, Cortex shows the notes that belong beside your cursor. Old ideas bloom exactly where they can be used.
Create from the canopy
Essays, talks, and products stop starting from blank pages. They emerge, almost assembled, from a forest you planted years ago.
Three organs of the second brain
Not features for their own sake — each one mirrors something your biological brain already does beautifully.
Bi-directional links
Every note lists not just where it points, but everything that points back. Context is never more than one click away.
Graph overview
Zoom out and see your thinking as a living constellation. Find the dense clusters — and the lonely ideas waiting for a friend.
Serendipity engine
A daily shuffle of forgotten notes, weighted toward what you're working on now. Rediscovery on schedule.
My Cortex graph looks like a map of my curiosity. When I feel lost on a project, I zoom out and literally seewhat I’ve been thinking about.
Tomas Reyes — PhD candidate, keeper of 6,412 notes
Plant a note today.
Harvest ideas for decades.
Free for your first 1,000 notes. Your graph, your files, your brain — exportable forever.
Grow your second brain