Security

Last updated 16 October 2026 · applies to wtrline.com and the Waterline app for Android

The safest data is data that's never collected. Waterline doesn't connect to your bank, doesn't need your real name, and works without an account at all. When you do sign in, your plan is encrypted on its way to us and while it's stored.

No bank connectionNo bank logins, card numbers or account numbers, ever. There is nothing for anyone to drain.

Your device firstWithout an account, your plan never leaves the browser you typed it into.

Encrypted in transit and at restHTTPS on every connection, and AES-256 encryption for plans saved to an account.

Locked to your accountThe database itself refuses to return one person's plan to anyone else.

On your device

Until you create an account, everything you enter is kept in your browser's own storage on that device, along with any backups. It is not sent to Waterline or anyone else, so there is nothing on our side to leak.

Browser storage is protected by your device, not by a separate password. On a shared or public computer, anyone using the same browser profile could open it. Use Delete all my data in the account menu before you leave a shared device.

If you sign in

Encrypted in transit. Every connection to wtrline.com and to our database uses HTTPS (TLS), so your plan can't be read on the way.
Encrypted at rest. Saved plans are stored with Supabase, which encrypts all customer data at rest with AES-256. Supabase is SOC 2 Type 2 compliant and ISO 27001 certified.
Row-level security. Every saved plan is tied to its account, and the database enforces a rule that it may only ever be read or changed by that account. Even a bug in the app couldn't show your plan to someone else.
Sign-in you already trust. Sign in with Google, a one-time email link, or a password. Passwords are handled by Supabase Auth and stored only as one-way hashes, never as text we could read.

What we don't claim

Waterline is not end-to-end encrypted. Your saved plan is encrypted in transit and at rest, but the database service holds the keys, because it has to send your plan back to you when you sign in on another device. If you'd rather no copy ever exists outside your own device, simply don't create an account. Waterline works fully without one, and you can still download a backup file to keep wherever you like.

No tracking, no ads

There are no analytics, advertising or tracking scripts, and no third-party cookies. Your plan is never sold, shared with advertisers, or used to profile you. The full list of services that help run the site is in the privacy policy.

You stay in control

Backups are made automatically before anything replaces your plan, and you can download one as a file at any time.
Undo follows every deleted bill, income, debt or one-off for a few seconds, so a mis-tap isn't a loss.
Delete account and Delete all my data in the account menu remove your plan from the database immediately. See deleting your data.

The Android app

The app opens wtrline.com in Chrome, full-screen, and is signed with our release key. Android checks that key against wtrline.com before it shows the site full-screen, so another app can't pass itself off as Waterline. It asks for no permissions beyond internet access.

Found a problem?

If you think you've found a security issue, please email privacy@wtrline.com with the subject Security report. We read every report and will reply as soon as we can. Please don't test against other people's accounts.