What does an API and Mobile QA Engineer do?
An API and Mobile QA Engineer tests mobile apps and the APIs and data behind them, finding defects that screen-level testing alone would miss.
Hire for depth beneath the screen. API validation, reliable automation, realistic device coverage, and backend data checks separate strong engineers from the broader QA pool.
Responsibilities
The role covers designing and running API tests, testing native and hybrid mobile apps across devices and operating system versions, building and maintaining automated tests, validating backend data, and reporting defects clearly.
Test the API
Validate requests, responses, status codes, contracts, authentication, error handling, and edge cases.
Automate API tests so they run with every build.
Test the app
Test iOS and Android apps across the devices, screen sizes, and OS versions customers use.
Cover installs, upgrades, offline behavior, notifications, and interruptions such as calls or poor connectivity.
Validate the data
Confirm that what the app shows and what the API returns match what is stored in the database and downstream systems.
Report defects with enough detail for developers to reproduce them quickly.
What test scope is the engineer joining?
The same title covers very different work. Before writing the description, define what the engineer will own.
- API, mobile, or both. A public or partner API program, a consumer mobile app, or an app whose quality depends on the services behind it.
- Automation expectations. Mostly manual and exploratory testing, or building and maintaining API and mobile automation in CI/CD.
- Device coverage. A handful of target devices, or broad coverage across manufacturers, OS versions, and form factors.
- Specialized testing. Whether performance, load, security, or accessibility testing is part of the role.
- Release cadence. App store releases on a schedule, or frequent API deployments that need fast feedback.
An engineer who will automate contract tests for a microservices API is a different hire from one who will test a consumer banking app across dozens of devices.