What to assess in a mobile engineer
Whether your app is cross-platform or native, the judgement a mobile engineer needs is similar: how the app behaves when things go wrong, and how changes reach users safely.
- App architecture: separating UI, state, data and networking so features can change independently.
- Offline-first behaviour: local storage, sync, conflict handling and clear states for the user.
- Releases: feature flags, staged rollouts, crash monitoring and what to do when a release goes bad.
- Performance: start-up time, memory, battery and smooth scrolling.
- Security: storing tokens safely and not trusting the client with anything that matters.
- Working with AI: checking generated code against the platform's rules rather than assuming it fits.
Screening questions for mobile engineers
Architecture questions can open a whiteboard beside the conversation. The screener reads the drawing and can ask about it.
- Sketch the architecture of a note-taking app that works offline and syncs across devices.
- A release doubles the crash rate on one Android version. Walk through the next hour.
- Where would you store a user's session token on a phone, and why there?
- How would you roll out a risky change to a small share of users first?
- An assistant generates a whole sync layer for you. How do you decide whether to trust it?
The mobile coding round
Coding rounds for mobile run a React Native (Expo) project with starter files and tests, in a Cursor-like IDE with a terminal, completions, file-aware chat and an agent. Hands-on code is JavaScript and TypeScript. If your team is native, the AI screen and the hiring manager round cover Swift or Kotlin experience in conversation.
You choose guarded or unguarded mode, and the server enforces it. Code is tinted by authorship, and the server reruns the tests at the end.
AI-fluency signals for a mobile engineer
| Signal | What it tells you about a mobile engineer |
|---|---|
| Time to first prompt | Whether they mapped the app's structure before asking for changes. |
| Prompt quality | Whether prompts give the platform, the constraint and the expected behaviour. |
| AI-generated share | How much of the final change came from accepted AI output. |
| Verification | Whether accepted code was tested or edited within 90 seconds. |
| Over-reliance flags | Large accepted blocks, such as storage or sync code, never reviewed. |
| Recovery | What they did when a suggestion failed a test or did not fit the platform. |
From scores to a decision
Fundamentals and AI fluency are scored separately and never averaged. The screen, coding round, hiring manager round and HR round sit on one scorecard, where the lowest verdict is shown next to the average. A named person records the outcome.
Questions
Can SynergicHire run native iOS or Android coding interviews?
No. Hands-on code is JavaScript and TypeScript, and mobile coding rounds use React Native (Expo). Native experience can be covered in the AI screen and the people rounds.
Can the AI screen cover mobile system design?
Yes. Put it in the plan and the screener opens a whiteboard when the section calls for it, then asks about what the candidate drew.
How much does a mobile coding round cost?
A coding round is 5 credits and covers up to 90 minutes. An AI screen is 1 credit, or 2 with voice.
Who decides whether a mobile candidate moves on?
A person. The AI gives advice with cited evidence, and a named person signs off every round and records every outcome.