Mobile App Security: What Every Founder Should Know

You don't need to be technical to ask the right security questions before your app ships — here's what actually matters.

Security in mobile apps is often treated as a checklist item at the end of a project, when it should be a design decision from day one. You don't need to understand cryptography to ask the right questions — you just need to know which mistakes are common and expensive to fix later.

The most frequent issue we see in code audits is secrets baked into the app itself: API keys, backend URLs or admin credentials hardcoded into the mobile bundle. Anyone can decompile an app and read these in minutes. The fix is straightforward — sensitive operations should happen on your backend, with the app only holding short-lived tokens, never permanent credentials.

The second common gap is authentication that trusts the client too much — checking permissions in the app's UI instead of on the server. A user can bypass any UI restriction by talking to your API directly, so every permission check needs to be enforced server-side, with the app UI only reflecting what the user is already allowed to do. The third is local storage: sensitive data (tokens, personal information, cached payment details) needs to sit in the platform's secure storage (Keychain on iOS, Keystore on Android), not in plain files or unencrypted databases on the device.

None of this requires a massive security budget — it requires treating these decisions as part of the architecture, not an afterthought. When we scope a new app, security requirements go into the technical plan alongside features, so nothing gets bolted on right before launch under time pressure, which is when most vulnerabilities slip through.