Mobile Engineer - Platform (Intermediate-to-Senior)
littlefish
Marketing & Communications
Sterling, VA, USA · Remote
Posted on May 11, 2026
About littlefish
littlefish is a Unified Commerce Platform for small and medium businesses across Africa, distributed through Financial Institution partners — banks, telcos, and insurers. We are live with 3 of the 5 major South African banks and onboarding 10–12 FI clients across the continent. The platform gives SMEs access to payments, invoicing, stock management, and expense management — tools previously only available to large corporations.
We are an AI-native engineering team. Every engineer operates as an Intent Architect: directing AI with precision, owning every decision about correctness, security, and quality, and building software that impacts real businesses across Africa. We are not vibe coders. The AI accelerates execution. The engineering judgment is yours.
Role Summary
The Mobile Engineer owns the mobile surface of the littlefish platform — the POS terminal app and the merchant companion app, both built in Flutter / Dart and shipping across a diverse Android device estate and iOS. Mobile remains a genuine specialist area: hardware diversity, white-labelling per FI client, and the realities of in-store payment flows make it materially harder than building a generic mobile app.
You think architecturally before you build, direct AI with precision, and review every line of generated output against your intent, the existing system, and the security requirements of a regulated fintech. The quality of what ships under your name is a direct reflection of the quality of the thinking behind it.
Key Responsibilities
Solution Design & Architecture
Decompose mobile problems and articulate the correct implementation approach — state model, navigation, persistence, platform boundaries, failure modes — before a single prompt is written.
Produce clear design artefacts: state diagrams, sync flows, API contracts, platform-channel interfaces.
Evaluate trade-offs across state management, offline strategy, native bridging, and white-label configuration.
Champion engineering standards: mobile security, observability, idempotency at the device-server boundary, pattern consistency across the apps.
Collaborate with the Principal Architect on decisions that cross the mobile-backend boundary or set new platform patterns.
Senior engineers are expected to drive end-to-end solution design for major mobile features and lead cross-functional design reviews.
Mobile Development
Design, build, and maintain features in Flutter / Dart across the POS terminal and merchant companion apps.
Own state, navigation, lifecycle, and persistence — including offline-capable flows where the POS must continue to function under poor connectivity.
Write and maintain platform channel code (Kotlin / Swift) for native integrations: payment hardware, secure elements, biometric auth, OS-level capabilities.
Handle the realities of mobile fintech: secure storage, certificate pinning, auth on constrained devices, careful handling of card and payment data.
Direct AI to generate widget, unit, and integration tests; validate they cover the failure modes that matter — bad networks, app backgrounding, hardware variation, edge cases on the payment path.
Hardware Diversity & POS Estate
Build for the POS terminal hardware estate — varied Android device variants with different OS versions, screen sizes, and peripheral capabilities.
Diagnose and resolve hardware-specific issues at the Flutter / native boundary.
Maintain device compatibility matrices and flag hardware constraints early in design.
White-Label & FI Configuration
Maintain visual consistency and brand compliance across white-labelled deployments per FI client — theming, assets, copy, and feature flags driven by tenant configuration.
Build and evolve the theming and configuration architecture so onboarding a new FI is configuration, not a fork.
AI-Native Engineering Practice
Direct AI with precise, contextual prompts that encode mobile system knowledge and the constraints of the regulated environment.
Review all AI-generated output critically — correctness, pattern alignment, mobile-specific pitfalls (state leaks, lifecycle bugs, platform differences), security implications.
Contribute to and uphold the team's evolving AI tooling standards, prompt review practices, and output quality gates.
Release Engineering & Observability
Own the Android (Play Store) and iOS (App Store Connect) release pipelines — signing, provisioning, internal and staged rollouts, store submission, crash recovery.
Instrument the apps for observability: crash reporting (Firebase Crashlytics or Sentry), performance monitoring, structured event telemetry that makes production behaviour debuggable.
Maintain release health post-launch and respond to crash spikes or regressions in the field.
Collaboration & Delivery
Work in cross-functional squads alongside Product, Design, QA, backend Platform Engineers, and SRE.
Participate in agile ceremonies: sprint planning, stand-ups, retrospectives, technical reviews.
Mentor junior Mobile Engineers — particularly on the discipline of directing AI well, native platform fundamentals, and reasoning about state.
Contribute to internal documentation, runbooks, and incident post-mortems.
Ask about the FI requirement, the SME use case, and the cashier or merchant journey before you build.
Skills and Qualifications
Experience
4–10 years of professional software development experience, with clear progression from intermediate to senior level on mobile.
Strong, demonstrable proficiency in Flutter and Dart — production apps shipped to real users at meaningful scale.
Working competence in Android (Kotlin) and / or iOS (Swift) — enough to write and own platform channel code, debug at the native boundary, and reason about OS-level behaviour.
Hands-on experience with state management at scale (Riverpod, Bloc, Provider, or similar) and offline-capable mobile architectures.
Experience owning release pipelines for Play Store and App Store Connect — signing, provisioning, staged rollout, crash response.
Experience with mobile security in a regulated context: secure storage, certificate pinning, biometric auth, careful handling of sensitive data.
Hands-on experience integrating with backend services over REST and async patterns; familiarity with event-driven backends is a plus.
Experience operating in fintech, payments, POS, or banking strongly preferred. POS terminal estate experience is a significant plus.
Technical Skills
Mobile core: Flutter, Dart, advanced widget composition, custom rendering where needed, lifecycle and memory discipline.
State management: Riverpod, Bloc, or Provider at production scale.
Native platforms: Kotlin (Android) and / or Swift (iOS), platform channels, native build systems (Gradle, Xcode), platform-specific debugging.
Persistence & sync: sqflite, Hive, Drift, or similar. Offline-first patterns, conflict resolution, sync queues.
Mobile security: secure storage (Keychain, Keystore), certificate pinning, biometric auth, secure handling of payment and card data.
APIs & data: REST, JSON, OAuth 2.0 / JWT, async / streams, idempotency at the device-server boundary.
Release & observability: Play Console, App Store Connect, Fastlane, Firebase Crashlytics or Sentry, structured event telemetry.
Tooling: Git, Android Studio, Xcode, Flutter DevTools, Azure DevOps CI/CD pipelines.
AI tooling: practical fluency with AI-assisted development workflows — prompt design, output review, and the discipline of directing AI rather than being directed by it.
Soft Skills & Leadership
Architectural thinking — decompose, identify boundaries, define constraints, and articulate the correct mobile approach before building.
Genuine review rigour — substantive checks against intent, existing patterns, and mobile-specific failure modes.
Ownership — quality, security, test coverage, release health, and pattern consistency across the apps are your problem to solve.
Curiosity about the business — you ask about the FI context, the merchant, and the cashier journey before you build.
You feel the weight of what the software does — when the POS is down, a merchant cannot trade.
Clarity — you simplify mobile complexity for engineers and non-technical stakeholders alike.
Constructive challenge — you raise risks, say no with reasoning, defend decisions on substance.
Senior bias for finishing and mentoring — you leave things better than you found them and contribute to a culture of engineering excellence.
To apply, please send your CV and a short note on why littlefish to hiring@littlefishapp.com. We do not require cover letters, but we do want to know what draws you to this role specifically — curiosity about the problem is part of what we are hiring for.
