Using the browser version
lunarlog runs in a browser at app.lunarlog.app — the same app, signed in to the same account, with one honest difference you should understand before using it on a shared computer: where a phone keeps your data on the device under its own lock, the browser keeps nothing at all — and the one credential it does hold (your signed-in session) sits in a cookie no page script can read, cleared the moment you sign out.
What the browser keeps
Nothing at rest. That is not a slogan — it is the client's build rule. No copy of your profiles or day entries is ever written to the browser's storage (no IndexedDB, no local storage, no offline cache), and an automated test re-asserts it on every change. What you see on screen is read live from your account, a window onto your data rather than a drawer holding a copy of it. When you close the tab, what was on screen is gone.
The sign-in itself is the narrowest a browser allows. While you are signed in, the working access token lives in the page's memory only and dies with the tab. The stay-signed-in part is a single HttpOnly, Secure, SameSite=Strict cookie — HttpOnly means no script running on the page, not even the app's own, can read it — and it is rotated every time it is used.
One more difference that matters: a phone keeps everything behind its screen lock; the browser adds no lock of its own. Anyone at the keyboard while your session is open can see what the window shows — which is why the next section is short and strict.
Shared computers
On a computer other people use, the habit stays the one it always was: sign out when you are done, every time. Signing out clears the session cookie and the in-memory token — nothing else needs clearing, because nothing else was ever stored.
And the judgment call no guide can make for you: a cycle log for a teenager belongs on her own devices. A shared family computer in a common room, used with her knowledge, is one thing; a borrowed work laptop is another. When in doubt, use your phone.
What the browser version is good for
A personal computer with a password-protected account of your own: comfortable keyboard-and-screen editing, catching up on a household's profiles from a laptop, or trying lunarlog before installing anything. When you go back to your phone, the same account puts the same profiles there — every change you made in the browser is already in your account, because that is the only place it ever was.
If you used the previous browser version in the past: it kept a local copy of your data in the browser. That copy was cleared automatically the first time you visited the new version, and the new one never writes one.