Client-side security in React Native is about reducing risk in layers, because no single measure secures an app. The JavaScript bundle ships to the device and can be inspected, so the first rule is simple: nothing secret belongs in it.
Key takeaways
- Keep secrets out of the JavaScript bundle and minimize sensitive data stored on-device.
- Protect authentication, networking, deep links, logs, and high-risk native flows.
- Use layered controls because no single client-side measure can secure an application.
Protect data at rest and in transit
Store tokens and sensitive values in the platform secure store — Keychain on iOS, Keystore-backed storage on Android — never in AsyncStorage or plain files. Minimize what you persist at all; the safest data is the data you do not store.
Use HTTPS everywhere and consider certificate pinning for high-value APIs to resist man-in-the-middle attacks. Keep API keys and secrets on the server; a key in the bundle is a public key.
Harden the high-risk flows
Protect authentication, deep links, and any native flow that touches money or personal data. Validate deep link parameters, scrub sensitive values from logs and crash reports, and treat the device as untrusted — jailbreak/root detection and anti-tampering raise the cost of attack but are defense in depth, not a guarantee.
Follow an established model like the OWASP Mobile Application Security guidelines so coverage is systematic rather than ad hoc.