Live

Lever.

The two most popular and effective breathing methods, built to work, when nothing else existed — a tool for someone who already knows the science and just needs it to get out of the way.

Try it live ↗

physiological sigh

The orb is the whole interface — just watch it and the rhythm teaches itself. Two inhales, one long exhale for calm; rapid pulses, then a still, glowing hold, for charge — press to end it early.

The breathing orb, running the real session rhythm. Tap Calm or Charge.

Every breathing app before this one either piled on techniques, streaks, and a paywall, or stripped down to a bare timer that never actually taught the rhythm. The void between those two failure modes is the point: nothing filled it, so Lever does — closer to a flashlight than a journal. Refusing everything the category treats as mandatory isn't a limitation of the build. It's the entire discipline the product is proving is possible.

01What it does

Calm, or charge.

Calm — physiological sigh — two inhales through the nose, one long exhale through the mouth. For acute stress, before sleep, between meetings.

Charge — cyclic hyperventilation — 20 deep breaths, exhale fully, hold lungs-empty as long as comfortable, recovery breath. For morning alertness, pre-workout, low energy.

Quick sigh — three physiological sighs, 30 seconds. Right now, in pocket, no thinking.

Two cards on the home screen, plus the Quick Sigh shortcut — that's the entire surface outside the session screens, and it stays that way on purpose.

02Restraint

Why only two.

The hard part was never what to build — it was what to refuse. Every one of these was considered in full and left out completely on purpose, because each would have pulled the tool back toward the bloated apps it exists to replace:

✕No streaks, badges, or gamification

✕No social features or sharing

✕No extra techniques — no box breathing, 4-7-8, alternate nostril

✕No journaling, mood logging, content library, or AI chatbot

✕No accounts, sync, subscription, or push notifications

Refusing everything the category treats as mandatory isn't a limitation of the build. It's the entire discipline the product is proving is possible.

03The build

One file, ~46 KB.

One file

A single ~46 KB HTML file — no build step, no bundler, no framework.

Vanilla

Plain JS, CSS transitions, inline SVG — no dependencies beyond Google Fonts.

Offline

Offline-capable once loaded; Add to Home Screen runs fullscreen.

iOS audio

Primes AudioContext on a user gesture so Safari’s autoplay rule doesn’t kill the phase tones.

iOS haptics

Uses the checkbox-switch trick (Safari 17.4+), since Safari has no Vibration API.

Wake Lock

Keeps the screen on through a whole session.

The interesting work is in the platform edge cases. Getting iOS audio, haptics, and wake-lock handling right is exactly the kind of "make it actually work on the user's device" detail that separates a shipped tool from a demo — unglamorous, easy to skip, and non-negotiable if the thing has to work every time.

See it live ↗

← All work