Mobile App Security Checklist: 16-Item Guide for iOS and Android

TL;DR

This 16-item checklist covers the most critical security issues in mobile apps: secure storage, network security, and code protection. 5 critical items must be fixed before launch, 5 important items within the first week, and 6 recommended items when you can.

Quick Checklist (5 Critical Items)

Use platform secure storageiOS Keychain, Android EncryptedSharedPreferences for secrets

Enforce HTTPS everywhereUse App Transport Security and Network Security Config

Implement certificate pinningPrevents man-in-the-middle attacks on compromised networks

Never hardcode API keysKeys in your bundle can be extracted by anyone

Use short-lived access tokensTokens should expire in 15-60 minutes

Secure Data Storage 4

Use platform secure storageiOS: Keychain. Android: EncryptedSharedPreferences or Keystore. Never use plain UserDefaults or SharedPreferences for secrets. How to secure mobile storage

Encrypt local databasesIf using SQLite or Realm, enable encryption. SQLCipher is a common choice for SQLite encryption. How to encrypt mobile databases

Clear sensitive data on logoutRemove tokens, cached user data, and session information when users log out. How to clear data on logout

Disable backup of sensitive dataExclude sensitive files from iCloud and Google backups. Users sharing devices could expose data. How to disable sensitive backups

Network Security 4

Enforce HTTPS everywhereUse App Transport Security (iOS) and Network Security Config (Android) to block HTTP. How to enforce HTTPS on mobile

Implement certificate pinningPin your API server certificates. Prevents man-in-the-middle attacks even on compromised networks. How to implement certificate pinning

Handle certificate rotationPlan for certificate updates. Pin backup certificates or use public key pinning for easier rotation. How to handle certificate rotation

Validate server responsesNever trust server data blindly. Validate types, formats, and ranges before using. How to validate API responses

Code and Secrets Protection 4

Never hardcode API keysKeys in your bundle can be extracted. Fetch configuration from your backend after authentication. How to secure mobile secrets

Enable code obfuscationUse ProGuard or R8 for Android. Swift code is harder to reverse but consider obfuscation for sensitive logic. How to enable code obfuscation

Detect jailbreak and rootDetect compromised devices. Consider limiting functionality or warning users on rooted or jailbroken devices. How to detect jailbreak and root

Implement runtime integrity checksDetect debuggers, hooking frameworks, and tampering. Make reverse engineering harder. How to implement runtime checks

Authentication and Sessions 4

Use short-lived access tokensAccess tokens should expire quickly (15-60 minutes). Use refresh tokens for session continuity. How to implement token refresh

Support biometric authenticationUse Face ID, Touch ID, or Android Biometrics for convenient but secure re-authentication. How to implement biometric auth

Implement secure session handlingInvalidate sessions on the server when users log out. Support remote session revocation. How to implement session management

Protect sensitive screensBlur or hide sensitive content in app switcher screenshots. Prevent screen recording where needed. How to protect sensitive screens

The Client Cannot Be Trusted

The fundamental rule of mobile security is that your app runs on user-controlled devices. Assume everything on the client can be inspected, modified, or bypassed. Your app bundle will be decompiled. Your network traffic will be intercepted. Your storage will be accessed.

Keep sensitive business logic, rate limiting, and authorization checks on your backend. The mobile app is a client interface, not a secure boundary.

Can someone reverse engineer my mobile app?

Yes. Both iOS and Android apps can be decompiled. Assume anything in your app bundle can be extracted. Never embed API keys, encryption keys, or sensitive logic that you want to keep secret.

Should I use code obfuscation?

Obfuscation slows down attackers but does not stop them. Use it as one layer of defense, but never rely on it to protect secrets. The real protection comes from keeping sensitive operations on your backend.

How do I handle API keys for third-party services?

Proxy third-party API calls through your backend when possible. If the mobile app must call third-party APIs directly, use keys with restricted permissions and monitor for abuse. Accept that these keys can be extracted.

TL;DR

Quick Checklist (5 Critical Items)

Secure Data Storage 4

Network Security 4

Code and Secrets Protection 4

Authentication and Sessions 4

The Client Cannot Be Trusted

Can someone reverse engineer my mobile app?

Should I use code obfuscation?

How do I handle API keys for third-party services?

Related Articles

API Security Checklist

Authentication Security Checklist

Certificate Pinning Guide

Check Your Mobile App Backend

Mobile App Security Checklist: 16-Item Guide for iOS and Android