Atendra S.

Mobile app developer specializing in Kotlin, SwiftUI Java, Bluetooth Low Energy (BLE), VoIP calling apps, and custom Android SDK development. I also have project experience with AOSP (Android Open Source Project). I build new applications, integrate mobile features, and troubleshoot existing production apps. ✅ Top Rated | 100% Job Success | $80K+ earned on Upwork | 12+ years in mobile app development I help businesses and product teams develop native Android applications, connect apps to Bluetooth devices, integrate calling and communication features, and maintain mobile products over the long term. CORE SERVICES • Native Android App Development Android application development using Kotlin and Java, feature development, REST API integration, Firebase integration, and maintenance of existing codebases. • AOSP (Android Open Source Project) I have worked on AOSP-based Android projects. Share your device, Android version, and required changes so we can assess how my experience fits your project. • Bluetooth Low Energy (BLE) Integration Bluetooth device connectivity and data exchange, troubleshooting BLE features, and integrating connected-device functionality into Android applications. Related experience includes NFC, OCR, and accessibility features. • VoIP App Development and Calling Features SIP and Linphone SDK integration for mobile calling applications, including audio calls, conference calling, messaging, and voicemail. I also work with WebRTC integration. • Custom Android SDK Development Reusable Android libraries and SDKs, third-party SDK integration, modular components, integration documentation, and support for adoption in existing apps. • Android App Maintenance and Bug Fixing Crash investigation, bug fixing, performance optimization, dependency updates, target API upgrades, and improvements to legacy Kotlin and Java applications. SELECTED PROJECT EXPERIENCE Android KYC SDK: Developed an Android SDK for Aadhaar-based authentication and integration into mobile applications. The work included authentication flows, API communication, and a customizable integration interface. VoIP Calling Application: Worked on a Linphone-based mobile application with audio calls, conference calling, messaging, voicemail, and fax features, using Linphone SDK alongside Sansay and Microsoft Azure. Kotlin Accessibility Application: Tested and improved an Android application with NFC, OCR, and BLE functionality. Client feedback highlighted my Kotlin knowledge, unit testing, responsiveness, and professionalism. Long-Term App Maintenance: Provided bug fixes and improvements for an Android interphone application. Additional project experience includes Wear OS GPS tracking and SOS functionality. ADDITIONAL MOBILE EXPERIENCE iOS app development and maintenance, Firebase Cloud Messaging (FCM), push notifications, Crashlytics, in-app purchases, background location tracking, Android TV, and AI feature integration. HOW WE CAN WORK TOGETHER I can help with a new Android app, a defined integration, an existing technical issue, or ongoing maintenance. I begin by reviewing the requirements and available code, identifying dependencies, and agreeing on the scope and first milestone. Send me your app’s purpose, the feature or issue you need help with, and your preferred timeline. We can discuss the technical approach and next steps.