Security — Simple Budget

Simple Budget holds your budget and, if you connect a bank, your bank transactions. This page explains how we protect them. Simple Budget is built and run by one developer, so the list below is also everyone who can reach our servers: one person.

Your bank login

You sign in to your bank in Plaid’s own screen, and your login goes straight to Plaid. The app and our server never see it.

Bank access keys

For each bank you connect, Plaid gives our server a key to fetch your transactions. We encrypt it with AES-256 before storing it and tie it to your connection, so it can’t be used anywhere else. It never leaves our server: it isn’t sent to your iPhone and never written to a log.

Encryption

Everything between the app, our server, Plaid, and Apple travels over encrypted connections (HTTPS). Our server runs on Cloudflare, which also encrypts the data it stores.

Signing in

You sign in with Apple, so there’s no password of ours to steal. The app proves who you are with a key that lasts 15 minutes and is renewed with a one-time key kept in your iPhone’s Keychain. Our server keeps only a fingerprint of it, and a session you don’t use for 60 days stops working.

Confirming it’s you

Connecting, reconnecting, or disconnecting a bank, and deleting your account, ask for Face ID, Touch ID, or your passcode first. Someone holding your unlocked iPhone can’t do them.

Who can see your data

Every request is checked against the budgets you belong to, and only a budget’s owner can connect or disconnect banks. At our end, only the developer can reach our servers, using accounts protected by passkeys or hardware security keys. We look at your data only if you ask us to help with a problem.

Messages from Plaid

When Plaid tells our server there are new transactions, we check Plaid’s signature before acting on it, and the message only ever starts a fresh sync.

Monitoring and updates

We watch our server’s error logs, which never contain bank data or keys, and keep the software the app depends on up to date. Changes are tested against Plaid’s test banks before they reach real ones.

Deleting your data

Delete your account in the app and we delete your data and end your bank connections at Plaid straight away. Backup copies expire within 30 days.

What the app collects, and how to delete it, is in the privacy policy.