iOS · TestFlight beta open

A calm focus timer that measures whether you actually got sharper.

Pick a depth. 30 seconds of reaction-time taps and an alertness rating before and after. Brevn tells you, in your own data, what kind of session, time of day, and amount of caffeine actually makes your brain work.

Join the TestFlight → What it does

30s

sharpness check

experiments

streaks · ads · noise

The session loop

Most focus apps time you. Brevn checks whether the timer actually did anything. You take a 30-second cognitive snapshot before the block, work for the depth you picked, and snapshot again. The delta is the verdict.

Pre-check. Five reaction-time taps + a 1-5 alertness rating. Takes 30 seconds.

Deep work block. 25 / 50 / 75 min. Optional movement breaks. iOS Live Activity on the lock screen so you don't reach for the phone.

Post-check. Same five taps, same alertness scale. See your delta. Honest about whether the block helped.

Reflection (optional). One line. What did you actually accomplish? Powers Trends without nagging.

What's in v0.2

Per-session caffeine

Log a one-tap dose. Brevn attributes it to sessions within a 90-minute window and tells you whether caffeine actually moves your numbers, or just your mood.

Auto-experiments

When your data shows a real swing, Brevn proposes a 7-day test (morning vs afternoon, 25 vs 50 minutes, caffeine vs no caffeine). One tap to start. No nags.

Paired experiments

Generate a pair code, send it to a friend. You each run the same experiment for 7 days. The app shows both verdicts side by side. No accounts.

Session tags

Tag a session "Work", "Personal", "Builder", anything. Trends breaks down quality by tag so you see which life domains pull your sharpest brain.

Weekly debrief

A short, honest read of the week. No streaks. No celebrations. Just what's true, what's changing, and where to look.

HealthKit integration

Sleep, HRV, resting heart rate. Median-split on your own baselines. See the days your body was actually rested versus the days you faked it.

Calm by design

Brevn is built on hard constraints, not soft preferences. The same constraints apply to every feature, every screen, every notification.

No streaks. A missed day isn't a moral failure. Streaks turn the tool into a master.
No exclamation marks. No celebrations. A good session is its own reward.
≤ 3 colors visible at once. The interface stays out of the way of the work.
Local-first. Your sessions live on your phone. Nothing leaves the device unless you explicitly share.
Honest verdicts. When the sample is too small, Brevn says so. No fake significance.

Try it

iOS TestFlight, public beta. Free, no signup required. The build is private-by-default; you can use Brevn without ever creating an account.

Open TestFlight →

Requires iOS 15.1+. Brevn is a one-person operation (Hyperfocused Engineer). Feedback goes straight to the builder.