Mobile Platform Expertise (iOS and/or Android)
You will be evaluated on how well you understand the platform you build for—frameworks, lifecycles, concurrency, and the nuances of UI architecture. Expect to demonstrate mastery of Swift/Objective‑C or Kotlin/Java, plus modern UI toolkits and testing strategies.
Be ready to go over:
- Concurrency and threading: Swift concurrency (async/await, Task, actors), GCD/Operations; Kotlin coroutines, structured concurrency, Dispatchers, thread safety.
- UI architecture: UIKit + SwiftUI composition, Jetpack Compose + ViewModel patterns, navigation, deep linking.
- Lifecycle and background work: App/scene lifecycles, WorkManager/background tasks, notifications, permissions, and OS constraints.
- Advanced concepts (less common): Accessibility (WCAG), device policy/MDM impacts, multi-window/multi-scene patterns, modularization and build performance.
Example questions or scenarios:
- "Diagnose and fix a UI jank issue on a list rendering complex cells."
- "Design a background sync that respects battery constraints and OS scheduling."
- "Refactor a view controller/fragment into a modern, testable architecture."
Architecture & Offline-First Systems
Salesforce mobile apps often operate in unreliable networks. You’ll be assessed on your ability to design sync models, conflict resolution, and resilient storage that keep users productive.
Be ready to go over:
- Data modeling and storage: Room/Core Data/SQLite, schema evolution, caching, pagination.
- Sync strategies: Delta sync, optimistic updates, idempotency, backoff, retries, and conflict resolution policies.
- API design: Contract design for mobile clients, versioning, pagination, error taxonomies, and telemetry for reliability.
- Advanced concepts (less common): CRDTs, eventual consistency at scale, sync logging/repair tooling, offline-first UX patterns.
Example questions or scenarios:
- "Design offline editing for a field work order with concurrent edits by multiple users."
- "Propose a conflict resolution policy for a hierarchical object graph."
- "Instrument and measure sync reliability across geographies."
Performance, Reliability, and Observability
You’ll be expected to diagnose hot paths and optimize latency, memory, and battery. Strong candidates demonstrate methodical use of profiling tools and data-driven decision making.
Be ready to go over:
- Profiling and optimization: Instruments (Time Profiler, Allocations, Memory Graph), Android Studio Profiler, flame charts, sampling vs tracing.
- Rendering performance: List virtualization, diffing, image decoding/caching, layout vs draw costs.
- Reliability and stability: Crash triage, ANR mitigation, watchdog timeouts, cold-start/warm-start improvements.
- Advanced concepts (less common): On-device feature flags, guardrail metrics (P95/P99), power modeling, adaptive prefetching.
Example questions or scenarios:
- "Walk through how you used Instruments/Profiler to find and fix a memory leak."
- "Reduce cold start time by 30%—where do you start, how do you measure?"
- "Contain a crash spike introduced by a poorly handled background task."
AI, Search, and Context-Aware Experiences
For teams like Slack Search and AI, interviewers will probe how you build findability and assistive experiences that feel native on mobile. Expect to discuss ranking tradeoffs, latency budgets, and responsible UX.
Be ready to go over:
- Search UX: Query understanding, incremental search, offline indexes vs server-driven results, ranking signals.
- AI-assisted flows: Prompt construction on-device vs server, privacy considerations, guardrails, and fallback behavior.
- Context and notifications: Smart actions from notifications, intents, deep links, device sensors for context.
- Advanced concepts (less common): Embeddings on-device vs edge, caching strategies for model inferences, A/B experimentation on mobile.
Example questions or scenarios:
- "Design a mobile search experience that stays responsive under poor connectivity."
- "Integrate AI suggestions into a compose box—how do you measure usefulness and avoid distraction?"
- "Select what runs on-device vs on the server given latency and privacy constraints."
Security, Compliance, and Enterprise Constraints
Enterprise mobility requires careful attention to authentication, data-at-rest, and policy enforcement. You’ll need to demonstrate familiarity with security from the first line of code.
Be ready to go over:
- Auth flows: OAuth/OIDC, token refresh, SSO, certificate pinning, secure storage (Keychain/Keystore).
- Data handling: PII protection, encryption, redaction in logs, safe crash reporting.
- Device and policy: MDM, remote wipe, jailbreak/root detection, conditional access.
- Advanced concepts (less common): Per-record encryption, secure background tasks, regulatory constraints across regions.
Example questions or scenarios:
- "Implement secure session management with seamless token refresh."
- "Handle crash logs without leaking sensitive data."
- "Design features to comply with device policies in an MDM-managed environment."