API Security for Kotlin, Swift, Flutter, and React Native Apps

Mobile apps are built with many different languages and frameworks.

Some teams use Swift or Kotlin for native development.
Others rely on Flutter or React Native to ship cross-platform apps faster.

Despite these differences, mobile APIs face the same security problems across every stack.

The common problem across mobile languages

No matter which language you use, mobile apps share one constraint:
they run on devices you don’t control.

This means:

• API keys shipped to the app can be extracted

• requests can be replayed outside the app

• endpoints can be automated by bots

• traffic can look legitimate

From a security perspective, a request from a Swift app is no safer than one from a React Native app.

Why API security is not a language problem

Developers often look for language-specific solutions:

• “How do I secure APIs in Swift?”

• “How do I protect Flutter APIs?”

• “What’s the best API security for React Native?”

In reality, the issue is not the language.
It’s the architecture.

If an API trusts client-side secrets or static tokens, it can be abused — regardless of whether the client is written in Kotlin, Swift, Flutter, or React Native.

Language-specific workarounds don’t scale

Each ecosystem offers partial solutions:

• obfuscation

• secure storage

• custom authentication flows

These techniques can raise the bar, but they don’t solve the core problem.

Once a request leaves the device, the API cannot reliably tell:

• which app sent it

• whether the device is real

• whether the behavior is expected

Security logic duplicated across platforms also increases complexity and maintenance cost.

A language-agnostic approach to mobile API security

Effective mobile API security should work the same way across all stacks.

A language-agnostic solution:

• does not rely on client-side secrets

• does not require platform-specific logic

• works with any app that can make HTTP requests

This makes security consistent, easier to reason about, and easier to maintain.

How ProtectMyAPI works across mobile stacks

ProtectMyAPI is designed to be language-agnostic by default.

It secures APIs by enforcing behavior and verifying requests externally, instead of trusting app code.

This makes it suitable for:

• Kotlin (Android)

• Swift (iOS)

• Flutter

• React Native

Any mobile app that communicates over HTTP can use the same security model.

No backend required, regardless of the stack

Many mobile teams add a backend solely to protect APIs.

ProtectMyAPI removes this requirement by enforcing access rules outside the application and without embedding secrets in the client.

This allows teams to:

• avoid backend complexity

• keep frontend code simple

• ship faster across platforms

Security becomes independent of the chosen language or framework.

Why this matters for cross-platform teams

Teams building multiple clients often struggle with:

• duplicated security logic

• inconsistent protections

• uneven behavior across platforms

A language-agnostic approach ensures:

• the same rules apply everywhere

• security is enforced centrally

• platform differences don’t introduce new risks

This is especially important for Flutter and React Native apps targeting multiple platforms from a single codebase.

When a language-agnostic solution makes sense

This approach works best when:

• your API is consumed by mobile apps

• you support multiple platforms

• you want consistent security guarantees

• you don’t want to maintain backend logic

It’s commonly used by indie developers and fast-moving teams shipping across iOS and Android.

One security model for every mobile stack

Mobile development evolves quickly. Languages and frameworks change.

API security should not depend on implementation details that change over time.

By decoupling security from the client language, it’s possible to protect APIs consistently — no matter how apps are built.

ProtectMyAPI exists to make mobile API security independent of frameworks, languages, and backend complexity.