Free & open source

Email that doesn't
spy on you.

A small, fast email app for Windows and Linux. Keep all your accounts in one place, search every message instantly, and run the whole thing from the keyboard.

Download for Windows View on GitHub

v0.1 preview · Windows · Linux build coming

Cursus + Compose MAIN Inbox 12 Drafts 3 Sent Archive Trash A Alex Morgan [email protected] Inbox 42 messages Search… ⌘K All People Newsletters SC Sara Chen 14:42 Q3 review — agenda & pre-reads Hey, sending the deck a day early so we can… JL Jamie Lopez 12:08 Re: deploy window for next sprint Sounds good — I'll prep the migration script and… ST Stripe 11:30 Receipt for $24.99 — invoice #4218 Thanks for your purchase. View the full invoice… MR Maya Reyes Yesterday Lunch tomorrow? Are you free between 13 and 14? I can come over… GH GitHub Mon Weekly digest — 14 issues updated Here's a recap of what changed in your projects… Q3 review — agenda & pre-reads SK Sara Chen [email protected] → me Hey, Sending the deck a day early so we can spend the meeting on the open questions instead of the slides. Three things I'd like your read on: Should we keep the soft-launch in the EU window? Pricing tier — keep three or collapse to two? Hiring — when do we open the senior backend role? Pre-reads attached. Talk Friday. — Sara PDF Q3-pre-reads.pdf 2.4 MB · click to download ↩ Reply · Reply all · Forward
Built for daily use

Everything you need.
Nothing you don't.

A full mail client. Multiple accounts, search across all of them, attachments, drafts, snooze, undo send. It just stops short of the parts that don't belong in a mail app.

Multiple accounts

IMAP over SSL or STARTTLS. Star a message, archive it, throw it in the trash. The change shows up on every other device immediately.

Send your way

Pick SMTP or Resend per account. Templates show up in the composer. After you hit send, you have up to thirty seconds to change your mind.

Instant search

Press Ctrl+K from anywhere. Results appear before you finish typing, across subjects, senders, snippets and the bodies you've opened.

Hands on the keyboard

Walk the inbox with j and k. Reply with r. Archive with e. The whole app stays usable without ever touching the mouse.

Truly portable

Drop the executable in any folder. Your accounts, drafts and search index live in a small cursus-files folder right next to it. Move the folder, take everything with you.

Passwords stay safe

Cursus stores your passwords in the operating system's secure keychain. They never sit in plain text inside the app.

Press Ctrl+K

Search that actually works.

Type half of what you remember. The right message shows up before you finish.

Search runs across subjects, senders, recipients and the bodies of every message you've opened. Click any result to jump straight to it.

  • Fast even with thousands of messages.
  • One click to index every body for full coverage.
  • Works the same across every account you've added.
q3 deck Esc RESULTS · 4 Q3 review — agenda & deck Sara Kim · Inbox · today 14:42 Re: Q3 board deck draft Ricardo Mendes · Sent · 2 days ago Final Q3 deck — please review Sara Kim · Inbox · 3 days ago Slides for Q3 all-hands Anaïs Tavares · Archive · last month
Hands stay home

The keyboard is the inbox.

Most actions are a single key. You walk through messages, open them, reply, archive, send, and search without ever reaching for the mouse.

The shortcuts are predictable and grouped by what they do, so you stop thinking about them within a few minutes of using the app.

j
Next thread
arrow down works too
r
Reply
a — all · f — forward
k
Previous thread
vim style, predictable
s
Star
! — toggle importance
e
Archive
selection or focused
⌘K
Search
Ctrl on Windows / Linux
c
Compose
opens fresh draft
Shift
Range select
+ j/k for bulk actions
22 shortcuts in total · full list inside Settings
The price of an inbox

Stop paying to read your own email.

Most mail apps want $30 a month to read messages your provider already delivers for free. Here's what they charge.

Superhuman
€30/mo
€360 / year

Premium positioning, status pricing.

Spark Pro
€22/mo
€264 / year · per user

"For top performers." The free tier keeps nudging you up.

Polymail Premium
$24/mo
$288 / year

Built for sales teams. Read receipts and tracking pixels are part of the deal.

HEY For You
$99/yr
~$8.25 / month

Pay to use one inbox at a fixed @hey.com address.

Canary Pro+
$100/yr
$10 / month

Privacy as the headline, paywall as the gate.

Mailbird Premium
€55/yr
often half-off — still recurring

Windows mail, with a SmartBar that keeps suggesting you pay more.

Cursus
Free. Always.

Open source. There's no tier above this one, no trial about to end, and no "Pro" version waiting to upsell you.

Download
What's missing

Everything that's not here is on purpose.

A mail app should read mail. The features that crept into other apps over the last decade add attack surface, complexity and noise without making the inbox better. Cursus skips them on purpose.

No assistants

No smart reply, no summaries, no auto categorisation. Your words are yours.

No cloud sync

Your data stays on your machine. Move it yourself, or don't.

No telemetry

The app never phones home. No usage pings, no analytics, no crash reports leaving your machine.

No tracking pixels

Remote images are blocked by default, so senders don't get a signal the moment you read the message.

Engineered to last

Native code. Web-class UI. SQLite under the hood.

Tauri 2 Rust React 19 TypeScript Tailwind v4 SQLite + FTS5 Apache-2.0

Take your inbox back.

Free. Open source. About 10 MB. No account, no signup. Point it at your IMAP server and start reading.

Download for Windows View source