Mobile appsec is the set of security practices and tools used to protect mobile applications throughout development, release, and operation. It covers code review, dependency and build-pipeline checks, runtime hardening, and validation of the app’s links to backend APIs. Because mobile apps run on devices the defender does not fully control, the attack surface includes source code, local storage, network traffic, and the runtime environment.
In practice, mobile appsec is usually split into specialized controls. Mobile SAST finds insecure code patterns before release, testing tools look for flaws in the app and API path, and shielding products make tampering, reverse engineering, and instrumentation harder after deployment. This matters because no single product protects every layer. Strong mobile appsec programs match controls to the threat model, often using standards such as MASVS to coordinate development and security teams and to catch issues early enough to fix them cheaply.