Role Overview

Durolt Technologies Pvt. Ltd., the technology arm of the Fonzel group, builds and operates a cloud-based smart locker platform used across Indian Railways, hospitality, financial institutions, and corporate/institutional clients. We are looking for a Junior App Developer to join our Pune-based product engineering team and work on the mobile, tablet, and Progressive Web App (PWA) applications that power the Durolt locker ecosystem.

This role is suited to a developer with 1–3 years of hands-on experience in React Native and/or React.js who is looking to grow under the guidance of senior developers, contribute to live product features, and build a strong foundation in mobile-first, cloud-first application development.

Key Responsibilities

- Develop and maintain mobile and tablet applications using the React Native framework for Android and iOS, under the guidance of senior developers.
- Build and maintain Progressive Web App (PWA) modules using React.js.
- Integrate REST APIs to connect app screens with the Durolt backend and tenant portal services.
- Assist in integrating third-party services such as Email, SMS, Payment Gateway, and FCM for push notifications.
- Support testing and debugging, and resolve bugs identified by QA or reported in production.
- Participate in Agile Scrum ceremonies – sprint planning, daily stand-ups, and sprint reviews.
- Collaborate closely with QA engineers, backend developers, and the Product team to ship features on schedule.
- Assist with app builds, releases, and version upgrades on the Google Play Store and Apple App Store.
- Write clean, well-documented code following team coding standards, and use Git for version control.
- Stay current with React Native/React.js updates and proactively suggest improvements to app performance and user experience.

Requirements & Qualifications

- 1–3 years of experience in React Native and/or React.js development (strong internship or project experience considered for candidates at the lower end of this range).
- Working knowledge of JavaScript/TypeScript and core React concepts – components, hooks, and state management.
- Basic understanding of REST API integration and asynchronous data handling.
- Exposure to native Android (Java/Kotlin) or iOS (Swift) is an added advantage, not mandatory.
- Familiarity with Git or other version control systems.
- Basic understanding of Agile/Scrum development practices.
- Willingness to learn cloud services (AWS Lambda, CloudWatch, RDS) and IoT-related integrations relevant to smart locker devices.




- Bachelor's degree in Computer Science, Information Technology, Engineering, or a related field (or equivalent hands-on project experience).

Domain Exposure – Smart Locker / IoT Stack (Good to Have)

Durolt's app runs on kiosk tablets embedded in physical locker hardware, so the platform goes deeper than a typical mobile app — offline-first data, MQTT-based device communication, and direct hardware integration. As a Junior App Developer you are not expected to have production experience across all of the areas below; you'll work under a senior developer's guidance to build this depth over time. Prior exposure, coursework, or personal-project familiarity with any of these is a strong plus and will fast-track your growth into a mid-level role.

1. Offline-first & local database

- SQLite hands-on: react-native-sqlite-storage, op-sqlite, WatermelonDB or Realm
- Schema migrations without data loss on already-deployed devices
- Sync engine: outbox/queue pattern, retries with backoff, idempotency keys
- Conflict resolution, clock skew, soft deletes/tombstones
- Encryption at rest (SQLCipher / encrypted Realm)
- Data retention and purge so the DB doesn't grow unbounded on kiosk devices

2. MQTT & realtime

- MQTT 3.1.1/5, QoS levels, and when each matters for a lock command
- Topic design, retained messages, Last Will & Testament for offline detection
- Persistent sessions, reconnect with backoff, keepalive tuning
- TLS, per-device credentials, broker ACLs
- MQTT over WebSocket; comparison with WebSocket/SSE/polling
- Command acknowledgement and de-duplication (a locker must not open twice)
- Brokers: Mosquitto, EMQX, HiveMQ, AWS IoT Core

3. Works-without-cloud behaviour

- Local-only unlock flow, cached permissions, queued audit logs when the cloud is unreachable
- Device-to-controller comms on LAN (local REST, TCP, on-prem MQTT broker)
- Feature flags / remote config to change behaviour without a store release

4. Hardware & peripheral integration

- BLE (react-native-ble-plx), NFC/RFID readers, QR/barcode scanning
- Camera pipeline for face capture, on-device liveness/quality checks
- Thermal/label printers,



USB serial or OTG for relay boards and locker controllers
- Background tasks, foreground services, wake locks, boot-time auto-start
- Kiosk mode / device-owner / lock task mode, MDM (Scalefusion, Knox, Android Enterprise)

5. Native layer depth

- Gradle, ProGuard/R8, ABI splits, signing; Xcode, CocoaPods, provisioning, entitlements
- Writing native modules and bridging vendor SDKs; JSI / Turbo Modules, New Architecture
- Debugging native crashes, not just JS errors

6. Security

- Android Keystore / iOS Keychain, no secrets in the bundle
- Certificate pinning, short-lived tokens for kiosk devices
- Root/jailbreak and tamper detection, screen recording protection
- Biometric/PII handling and consent (relevant given face auth)

7. APM & observability

- Sentry / Crashlytics / Bugsnag with source map upload in CI
- Crash-free session rate, ANR tracking, release health per version
- Offline log buffering with later upload, remote log pull from field devices
- Custom events: unlock attempt, unlock success, sync failure, hardware timeout
- Error boundaries and graceful degradation when network or hardware is unavailable

8. Release engineering

- OTA updates (CodePush / EAS Update) and knowing what cannot ship OTA
- Fastlane or EAS pipelines, staged rollouts, forced-upgrade handling for fleets
- Old app versions still talking to the current API

9. Testing depth

- Jest + React Native Testing Library; Detox or Maestro for E2E
- Testing offline paths and hardware failures with mocks
- Physical low-end Android device testing, not just simulators

10. Kiosk UX

- Accessibility, large-touch layouts, multi-language
- Clear offline/error states for a user standing at a locker

11. Performance

- Hermes, bundle size, startup time (matters on cheap kiosk tablets)

What We Offer

- The opportunity to work on Durolt's smart locker and IoT platform, deployed with enterprise clients such as Railways, Nayara Energy, Nokia, Bharat Electronics Limited, and the Aditya Birla Group.
- Hands-on mentorship from senior developers and exposure to the complete mobile app development lifecycle.
- A cooperative, fast-paced product engineering environment.
- Competitive compensation package.
- Learning and growth opportunities across mobile, cloud, and IoT technologies.

How to Apply

Please send your updated resume, along with a portfolio or GitHub link, to [email protected] with the subject line “Application – App Developer (React Native/React.js)”. Shortlisted candidates will be contacted within 7 working days.

📌 App Developer – React Native / React.js (Pune)
🏢 Fonzel
📍 Pune