How do you secure React Native applications?

Question

Accepted Answer

Securing React Native apps involves protecting **data** (secure storage, encrypted transmission), handling **secrets and tokens** safely, securing the **JavaScript bundle**, and following mobile security best practices. Security matters as apps handle sensitive user data.

## Data and credential security

```text
✓ SECURE STORAGE for sensitive data — react-native-keychain / expo-secure-store
  (encrypted, keychain/keystore) — NOT AsyncStorage (which is NOT encrypted) for tokens/
  credentials (a common mistake)
✓ HTTPS/TLS for all network traffic; certificate pinning for sensitive apps
✓ Don't HARDCODE secrets/API keys in the JS — the JS BUNDLE can be extracted/inspected
  (anything in the app can be reverse-engineered) → keep real secrets on the SERVER
✓ Secure auth: OAuth, short-lived tokens, secure refresh; biometric auth where appropriate
```

## Code and platform security

```text
✓ The JS bundle is shipped with the app → assume it can be READ:
  → don't embed sensitive logic/secrets; sensitive operations belong on the server
  → OBFUSCATE (limited protection); detect tampering/jailbreak/root for high-security apps
✓ Validate inputs; secure deep links (validate params); be careful with WebViews
✓ Keep DEPENDENCIES updated (npm vulnerabilities); audit packages (supply chain risk)
```

## Server-side and general

```text
✓ NEVER trust the client → validate and authorize on the SERVER (the client can be
  tampered with — a fundamental principle)
✓ Least privilege; protect APIs (auth, rate limiting); don't leak data in logs
✓ Handle permissions minimally; protect user privacy
```

## Why it matters

Understanding how to secure React Native applications is important senior-level knowledge because **apps handle sensitive user data** on devices that can be compromised, so security is essential with real consequences if neglected. **Data and credential security** is fundamental: using **secure storage** (react-native-keychain/expo-secure-store, encrypted) for sensitive data like tokens — **not AsyncStorage** which is unencrypted (a common, serious mistake) — using **HTTPS/TLS** for all traffic, and crucially **not hardcoding secrets in the JavaScript** (since the **JS bundle ships with the app and can be extracted and inspected** — anything in the app can be reverse-engineered, so real secrets must stay on the server).

This JS-bundle-is-readable point is a critical React-Native-specific security consideration. **Code and platform security** reinforces this: assuming the JS bundle can be read (so sensitive logic and secrets belong on the server, not the client), validating inputs and deep links, being careful with WebViews, and keeping dependencies updated (npm supply-chain risk). **Server-side validation** is essential: the fundamental principle that you **never trust the client** (which can be tampered with) and must validate and authorize on the server — a cornerstone of security that's especially relevant given the client is a reverse-engineerable mobile app.

Understanding these layered practices — secure storage, encrypted transmission, keeping secrets server-side, server-side validation, and dependency security — reflects the security mindset needed for apps handling sensitive data.

Since React Native apps handle sensitive data on compromisable devices (with the JS bundle being inspectable), and since proper security (secure storage not AsyncStorage, no hardcoded secrets, server-side validation, HTTPS) prevents the real vulnerabilities that neglecting it causes, understanding how to secure React Native applications is important, security-critical senior-level knowledge — essential for protecting user data, reflecting the security responsibility expected for senior roles, and addressing the genuine mobile-app risks (especially the readable JS bundle and untrusted client) inherent in React Native apps.