Local-first · Markdown · for people who think

Your ideas deserve
better than folders.

Cortex is a notes app for thinking, not filing. Capture a thought in seconds, let it connect to everything you already know, and keep all of it as plain Markdown files you own — readable in any editor, on your disk, forever.

Coming soon on theApp Store Open the web app →
⌘K to jump anywhere · No account · Works offline
Notes/Pricing.md --- tags: [pricing, strategy] --- ## Usage-based pricing - aligns cost with value - see [[Revenue model]] - contrast w/ [[Flat tiers]] - open Q: [[Churn]]? #strategy Revenue model Flat tiers Churn Cohorts
a single note, and everything it touches
The quiet problem

Your best thinking is scattered
across a dozen apps.

A note here. A screenshot there. A link saved to read later and never read. The idea you had last month is in there somewhere — you just can't find it, and nothing reminds you it exists. Folders made sense for files. They never made sense for thoughts.

note-to-self.txt
screenshot-2026-04-12.png
"read later" bookmark
meeting_notes.docx
voice memo 0:42
half-finished idea
that thread you starred
a PDF you highlighted

Cortex turns the scatter into one connected memory — and quietly helps you remember what's in it.

01

Capture in seconds

Open, type, done — under three seconds. Every thought becomes a durable file the instant you save.

02

Connect over time

Link ideas with [[ and watch structure emerge — backlinks, a graph, a canvas.

03

Own it forever

Plain Markdown on your disk. No account, no lock-in, no servers between you and your notes.

How it works

Four motions. The whole practice.

Capture

Get the thought down before it's gone.

A quick-capture sheet and a system share sheet mean a thought goes from your head to a file in under three seconds. Share a link or a paragraph from any app and it lands in your inbox, ready to connect later.

→ saved as Inbox/<id>.md — yours from the first keystroke

Quick capture
# jotted on the train, 7:41am
usage pricing might fix the
[[Churn]] problem — test it
against [[Q3 goals]] #idea
Connect

Links turn notes into a network.

Type [[ and Cortex autocompletes a link to any note. Every link creates a backlink with the surrounding context, and an interactive graph draws itself from the connections. Rename a note and every inbound [[link]] updates automatically — nothing breaks.

Backlinks resolve by title, case-insensitive · links inside code stay literal

Backlinks → Revenue model.md
3 notes link here
← Pricing.md      "see [[Revenue model]]"
← Q3 goals.md     "depends on [[Revenue…]]"
← Investor memo   "our [[Revenue model]] is"
Own

The files are the database.

Everything is plain Markdown with YAML frontmatter and open JSON Canvas for boards. The search index lives in a regenerable .cortex/ folder — delete it and you lose nothing, because your words were never trapped in a database.

No lock-in. Ever.

~/Cortex
Daily/      2026-06-22.md
Inbox/      01HF…3K.md
Notes/      Pricing.md  Revenue model.md
Canvas/     Roadmap.canvas
.cortex/   # index — rebuilt from files
Find

Search by words — or by meaning.

Keyword search is instant and free. ✦ Smart search finds notes by meaning, not exact words — so the half-remembered idea surfaces even when you've forgotten what you called it. Both run entirely on your device.

Smart search uses on-device embeddings — no text ever leaves your machine.

✦ Smart search
"how should we make money?"

→ Usage-based pricing     0.81
→ Revenue model           0.77
→ Investor memo · pricing  0.71
# none of these contain those words
How ideas compound

One thought, six months later.

Nothing here is a feature. It's what happens when capture is frictionless, links are free, and the AI works quietly in the background — on your device.

As you write, Cortex resurfaces a related note you'd forgotten — at most one, never a popup storm. Over time, its Insights notice the themes you keep returning to and the notes you should connect but haven't.

Mon, 9:41am

Capture a thought

"Usage-based pricing might reduce churn." Three seconds, one file, done.

Two weeks later

Add context

You paste a benchmark and a quote into the same note. It's growing without effort.

A month in

Link related ideas

You write [[Revenue model]] and [[Churn]]. The graph quietly redraws.

While writing something new

Discover a pattern

Cortex surfaces the pricing note you forgot — and Insights flags that you keep returning to #strategy.

Six months later

Make something real

The strategy memo half-writes itself. The thinking was already there, connected.

Built for momentum

Everything a keystroke away.

Five surfaces, reachable by number. ⌘K jumps to any note from anywhere. The app gets out of the way so the thinking doesn't.

"It's the first notes app that feels like it was built by people who actually take notes." — what we're building toward
1TodayYour daily note — start here.
2InboxEverything captured, waiting to be connected.
3NotesThe full library, plus canvases and templates.
4GraphYour knowledge as a living, pannable map.
5InsightsHubs, orphans, recurring themes, notes to connect.
⌘KSwitcherFuzzy-jump to any note, instantly.
In practice

A vault is whatever you think in.

Because it's just files and links, Cortex becomes the shape of your work — a research system, a writing studio, a second memory.

A research system

PhD · literature & argument
Sources/  [[Deci 1985]]
Claims/   [[Intrinsic motivation]]
Threads/  [[Open questions]]
# every claim cites its source

A writing studio

Essayist · drafts that link
# The case for slowness
seed: [[Attention]]
evidence: [[Deep work]]
counter: [[Flow myths]]
#draft

A second memory

Founder · decisions & people
People/   [[Sam — design]]
Decisions/ [[Why usage pricing]]
Daily/    today links it all
Pricing

The core is free. Forever.

Owning your notes is never paywalled. Pay only when you want sync and the on-device AI — and start with a 7-day Plus trial, no card required.

Free
$0
Your data, yours
  • Markdown vault & editor
  • Backlinks, daily notes
  • Keyword search
  • Graph, canvas, templates
  • Quick switcher (⌘K)
Most chosen
Plus
$8 / month
The thinking tier
  • Everything in Free
  • Sync across your devices
  • ✦ Smart (meaning) search
  • Forgotten-knowledge recall
  • Insights & unlimited storage
Believer
$199 once
Lifetime + support
  • Everything in Plus, forever
  • Early-access builds
  • Publish add-on
  • Supporter badge
Teams
Talk to us
For collaborators
  • Everything in Believer
  • Shared vaults
  • Admin & SSO
The promise under everything

Your notes live as plain files on your disk. The AI runs on your device. Nothing is uploaded, nothing is tracked, no account is required. Delete Cortex and your knowledge is still right there — in a folder you own.

what stays on your machine
✓ your Markdown files
✓ the search index (.cortex/, rebuildable)
✓ embeddings for Smart search
✓ Forgotten-knowledge signals
# sync is optional, through a folder
# you choose — never our servers

Runs natively on iOS and in the browser — the same engine, compiled to WebAssembly, over real .md files via the File System Access API.

Why Cortex

Most apps store your notes.
Cortex helps you think.

The difference isn't one more feature. It's a stance — recall that works the moment you write, on your own device, over files you'll always own.

An ordinary notes app
  • Stores what you type, then waits for you to find it again.
  • Connections and recall assembled from plugins, themes, and setup.
  • The clever features run on a server — your thinking leaves your device.
  • Your notes take the shape of someone else's format.
Cortex
  • Resurfaces the notes you'd forgotten — quietly, as you write.
  • Semantic search and forgotten-knowledge recall are built in. Nothing to configure.
  • The AI runs on-device. No account, no cloud, nothing uploaded.
  • Plain Markdown on your disk. Leaving is just copying a folder.
Questions

The things people ask first.

Where are my notes actually stored?
As plain Markdown (.md) files in a folder you choose — with YAML frontmatter and open JSON Canvas for boards. In the browser, Cortex writes real files through the File System Access API (or private file storage). You can open, edit, and back them up with any tool. The search index lives in a separate .cortex/ folder you can delete at any time without losing a word.
Is the AI sending my notes anywhere?
No. Smart search and the resurfacing of forgotten notes run on-device using local embeddings. Nothing leaves your machine by default, there's no account, and there's no tracking.
How is Cortex different from other notes apps?
Most tools store what you write and wait for you to come find it again — and their smart features, where they exist, run on a server. Cortex is local-first and Markdown-first, but the recall and search are built in and ambient, not assembled from plugins or setup. Semantic search and forgotten-knowledge recall work out of the box, on-device, with a hard "your files are yours" guarantee. It's opinionated about helping you think, not just store. (More on that in Why Cortex.)
How does sync work without your servers?
Sync reconciles changes through a folder you control — iCloud Drive, Dropbox, or a synced directory — with a conflict-free merge layer so concurrent edits never collide. Your content never has to pass through Cortex servers. (Sync is part of Plus.)
Can I import from another app — and leave?
Yes. Any Markdown vault drops straight in. And because everything is open files and standard formats, leaving is just copying a folder. Lock-in is structurally impossible.
What does it cost?
The full local-first core is free forever. Plus is $8/month and adds Sync, the on-device AI features, and unlimited storage; Believer is a one-time $199 for lifetime access. A 7-day Plus trial starts automatically — no card needed.
Start thinking in connections

Where ideas go to grow.

Free forever. No account. Your notes stay plain files you own. Begin with a single thought.

Coming soon on theApp Store Open the web app →