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Senior mobile engineer with 12+ years of experience building production-grade iOS and React Native applications, with hands-on experience in BLE/Bluetooth, NFC, native iOS development, third-party SDK integrations, subscriptions, and complex mobile features. I help startups and product teams build, stabilize, and ship reliable mobile applications especially projects where React Native needs to work closely with native iOS/Android capabilities, hardware devices, or third-party SDKs. I don't just focus on completing tickets. I take ownership of the mobile side of a product, understand the existing architecture, identify technical risks, and build solutions that are stable, maintainable, and ready for real users. WHAT I SPECIALIZE IN ---------------------------- React Native: • React Native with JavaScript / TypeScript • iOS & Android development • Native modules and bridges • Third-party SDK integrations • Performance optimization and debugging • Architecture, refactoring, and production maintenance • React Native / Expo upgrades Native iOS: • Swift, SwiftUI, UIKit, Objective-C • CoreBluetooth / BLE • CoreNFC / NFC • HealthKit • Apple Sign In • StoreKit & In-App Purchases • Push Notifications • Background capabilities • App Store submission and rejection fixes BLE / Hardware Integrations: • BLE device discovery, pairing, and connection • Reconnection and connection-state handling • Characteristic read/write and notifications • Real-time device data streams • Hardware-to-mobile communication • Wearable and IoT integrations • React Native + native Bluetooth modules Subscriptions & Monetization: • RevenueCat • StoreKit • Apple In-App Purchases • Paywalls and subscription flows • Entitlements and Restore Purchases API & Mobile Services: • REST & GraphQL API integration • Firebase Authentication, Firestore and Messaging • Supabase integration • OAuth and third-party services • Push notifications and real-time synchronization I primarily focus on mobile engineering and API/service integration, rather than positioning myself as a backend developer. TYPES OF PROJECTS I HELP WITH ------------------------------------------- • New React Native applications from Figma/designs or existing MVPs • Existing app rescue, stabilization, and refactoring • Native iOS functionality inside React Native applications • BLE, Bluetooth, NFC, and hardware integrations • Wearable and connected-device applications • RevenueCat, StoreKit, and subscription implementation • Real-time chat and data synchronization • Location, maps, and geofencing • Difficult React Native and iOS production issues • React Native / Expo upgrades and native build issues • App Store submission and App Review rejection issues HOW I APPROACH EXISTING CODEBASES ---------------------------------------------------- When taking over an existing application, I don't automatically recommend a rebuild. I first understand what is already working, where the risks are, and which parts can be safely reused. Then I separate the work into: Fix → Refactor → Replace → Build This keeps development practical and avoids rebuilding components that don't actually need to be rebuilt. For new applications, I focus on creating a clean foundation that can support future features without unnecessarily over-engineering the MVP. MY BACKGROUND ----------------------- Before becoming a full-time freelancer, I spent 9 years as a full-time mobile engineer, progressing from Junior iOS Developer to Senior iOS and React Native Developer at a product-focused software company. I wasn't job-hopping. I was building. During those years, I worked on production applications, made architectural decisions, integrated hardware devices, implemented native functionality, and solved the problems that appear when applications have real users and real production constraints. In 2023, I moved into freelancing with one goal: Bring the same engineering discipline and product mindset to clients that expect more than simply writing code. Since then, I've worked with startups and product teams on new applications, existing product improvements, hardware integrations, debugging, and production releases. WHY CLIENTS WORK WITH ME -------------------------------------- 🏅 Top Rated on Upwork ✅ 100% Job Success Score ⏱️ 2,800+ Upwork hours 💰 $30K+ earned on Upwork I work best with teams looking for more than someone who simply completes tickets. I take ownership, communicate technical trade-offs clearly, identify problems early, and focus on delivering a product that is stable, maintainable, and ready to grow. If you're building a new mobile product, taking an MVP toward production, integrating BLE/NFC or native functionality, or dealing with an existing codebase that needs to be stabilized, I'd be happy to take a look. Send me your requirements or an invite, and I'll give you a straightforward technical assessment and a practical path forward. Let's build something worth downloading.

I have more than 11 years of experience in Embedded Firmware development and worked on various MCU from Nordic, Microchip, TI, Cypress and Linux SBC like Raspberry Pi. I have special interest in IOT space.

I design and build Flutter mobile applications that communicate with real-world smart devices using Bluetooth (BLE) and cloud IoT platforms. With 9+ years of mobile development experience, I help companies deliver stable, scalable, and production-ready mobile apps especially in IoT, BLE, and device-connected systems. 🧠 What I Specialize In Flutter & Mobile Architecture - Scalable Flutter apps using Clean Architecture - Modern state management (Riverpod, Bloc, Provider, GetX) - Platform channels for native Android & iOS integrations - Performance optimization and maintainable codebases BLE & Smart Device Integration - Bluetooth & BLE scanning, pairing, and reconnection logic - GATT services, characteristics, notifications - Reliable communication with smart devices (fans, sensors, health-care devices) IoT & Cloud Connectivity - AWS IoT Core integration using MQTT - Secure device-to-cloud-to-app communication - Telemetry, commands, and real-time updates - ThingsBoard SDK for device management and data visualization Backend & Real-Time Features - REST API integration - Authentication flows - Real-time communication (Socket-IO, Firebase) - Offline-first data sync strategies CI/CD & Release Automation - GitHub Actions for Flutter projects - Android & iOS Xcode build automation - Versioning and release pipelines - TestFlight & Play Store deployments 🛠 Technical Stack - Flutter / Dart - Android: Kotlin, Java - State Management: Riverpod, Bloc, Provider - BLE, NFC - AWS IoT Core, MQTT - ThingsBoard - SQLite, Drift, Hive - Firebase, AWS S3 - GitHub, GitLab, Bitbucket - CI/CD (GitHub Actions, Xcode) 🤝 Who I Work Best With - IoT startups & hardware companies - Agencies needing a senior Flutter engineer - Teams that need architecture ownership, not just task execution If your app involves BLE devices, smart hardware, or cloud-connected systems, I can help you build it right the first time. 🏆 Upwork Credentials - ⭐ Top Rated Freelancer (Top 10% on Upwork) - ✅ 100% Job Success Score - 💬 100% Client Recommendation Rate - 🌍 Long-term international client collaborations

I've built and shipped mobile apps used by millions — including apps for boAt (India's #1 wearable brand), the Government of India's national education platform (DIKSHA), and Zed (Dubai's premium taxi app), where I was a core developer and helped take the iOS app from a 3.2-star to a 4.6-star rating, now serving around 80,000 monthly active users. Over 7+ years I've specialized in the harder parts of mobile development that most freelancers avoid: BLE / IoT & Wearables — I built the iOS apps for boAt's smartwatch line (boAt Wearable, boAt Hub): CoreBluetooth device pairing, real-time health/activity data sync, firmware communication, barcode-based device onboarding, and offline storage with Realm/Core Data. If your product talks to hardware, I've solved these problems before. AI-Powered Mobile Features — On India's national education platform (DIKSHA) I integrated an AI chatbot, voice-AI conversations, and Bhashini (India's government speech-AI stack) for multilingual voice interaction. Earlier, I shipped ULT — a calling app with real-time voice and chat translation, where a user speaks or types in one language and the receiver hears or reads it in their own, live, without lag. Real-Time & Location Apps — Live driver tracking for a food-delivery app in Italy (1Food.it), ride booking and tracking for Zed in Dubai, Google Maps/Places integrations, push and silent notifications. Payments & Monetization — In-App Purchases (StoreKit), Razorpay, subscription flows. I work US/EU-friendly hours, communicate proactively with regular updates and honest estimates, and I've managed full project lifecycles — requirements, architecture, development, App Store/Play Store release, and post-launch optimization. Tech: Swift, SwiftUI/UIKit, Flutter, Dart, CoreBluetooth, Firebase, REST APIs, Realm/Core Data, Google Maps, StoreKit/IAP, NEVPN, push notifications, localization at national scale. Let's talk about your app — I typically respond within a few hours.

🚀 Top Rated Plus | ESP32 & STM32 Firmware Developer | Embedded Systems & IoT Engineer | 6+ Years Experience Looking for an experienced Embedded Firmware Developer who can turn your idea into a reliable, production-ready product? I'm a Top Rated Plus Embedded Systems & IoT Engineer with over 6 years of experience developing embedded firmware, designing custom hardware, and building IoT products for startups, SMBs, and enterprise clients worldwide. I specialize in: • ESP32 Firmware Development • STM32 Firmware Development • Embedded C & C++ • ESP-IDF • FreeRTOS • BLE • MQTT • IoT Product Development • PCB Design • LVGL • TouchGFX • AWS IoT I provide complete end-to-end engineering services, from hardware design and firmware development to cloud connectivity, GUI development, testing, and production support. ━━━━━━━━━━━━━━━━━━━━━━ WHY CLIENTS HIRE ME ━━━━━━━━━━━━━━━━━━━━━━ • Top Rated Plus Freelancer with a proven track record • Production-Ready Firmware • Clean, Maintainable & Well-Documented Code • Fast Communication & Daily Progress Updates • Strong Debugging & Problem Solving Skills • End-to-End Product Development • Long-Term Technical Support ━━━━━━━━━━━━━━━━━━━━━━ FIRMWARE DEVELOPMENT ━━━━━━━━━━━━━━━━━━━━━━ Programming Languages • C • C++ • Python Expertise • Embedded Firmware Development • Bare-Metal Programming • FreeRTOS • Zephyr RTOS • ESP-IDF • STM32Cube • Arduino Framework • PlatformIO • Mbed OS • Bootloader Development • Secure Boot • OTA Firmware Updates • Device Driver Development • Memory Optimization • Low Power Design • Firmware Optimization ━━━━━━━━━━━━━━━━━━━━━━ MICROCONTROLLERS ━━━━━━━━━━━━━━━━━━━━━━ Espressif • ESP32 • ESP32-S2 • ESP32-S3 • ESP8266 STMicroelectronics • STM32F0 • STM32F1 • STM32F3 • STM32F4 • STM32H7 • STM32WB • STM32U5 Nordic • nRF51 • nRF52 Microchip • PIC12 • PIC16 • PIC18 • PIC24 • dsPIC30 • dsPIC33 • PIC32MX • PIC32MK • PIC32MZ ━━━━━━━━━━━━━━━━━━━━━━ COMMUNICATION PROTOCOLS ━━━━━━━━━━━━━━━━━━━━━━ • UART • USART • SPI • I²C • I²S • CAN Bus • USB (CDC, HID, DFU, MSC) • Ethernet • RS485 • Modbus RTU • Modbus TCP • OneWire • ADC • DAC • PWM • SD Card • SDMMC ━━━━━━━━━━━━━━━━━━━━━━ WIRELESS & CONNECTIVITY ━━━━━━━━━━━━━━━━━━━━━━ • Bluetooth Low Energy (BLE) • WiFi • MQTT • HTTPS • WebSockets • LoRa • LoRaWAN • Cellular (4G/5G) • Zigbee • Z-Wave Cellular Modems • SIM7600 • EC25 • EC200U • A7672 Series ━━━━━━━━━━━━━━━━━━━━━━ CLOUD & IoT ━━━━━━━━━━━━━━━━━━━━━━ • AWS IoT Core • Google Cloud • MQTT Brokers • REST APIs • HTTPS • WebSockets • Remote Device Management • Secure Device Provisioning • OTA Firmware Updates ━━━━━━━━━━━━━━━━━━━━━━ GUI DEVELOPMENT ━━━━━━━━━━━━━━━━━━━━━━ • LVGL • TouchGFX • Qt for MCUs Experience • Animated User Interfaces • Touchscreen Applications • Dashboards • TFT Displays • OLED Displays • E-Ink Displays • Capacitive Touch • Resistive Touch ━━━━━━━━━━━━━━━━━━━━━━ HARDWARE & PCB DESIGN ━━━━━━━━━━━━━━━━━━━━━━ Tools • Altium Designer • KiCad Services • Schematic Design • PCB Layout • Prototype Development • Hardware Bring-up • Design for Manufacturing (DFM) • Production Support ━━━━━━━━━━━━━━━━━━━━━━ INDUSTRIES ━━━━━━━━━━━━━━━━━━━━━━ • Industrial Automation • Consumer Electronics • Medical Devices • IoT Products • Smart Home • EV & Automotive Electronics • Wireless Products • Energy Monitoring • Sensor Networks ━━━━━━━━━━━━━━━━━━━━━━ SERVICES I OFFER ━━━━━━━━━━━━━━━━━━━━━━ • ESP32 Firmware Development • STM32 Firmware Development • Embedded C/C++ Development • ESP-IDF Development • FreeRTOS Development • BLE Firmware Development • MQTT IoT Development • Device Driver Development • Bootloader Development • OTA Firmware Updates • PCB Design • Hardware Design • Embedded GUI Development • LVGL Development • TouchGFX Development • Cloud Integration • Firmware Debugging • Performance Optimization • Legacy Firmware Modernization • Complete IoT Product Development If you're looking for an ESP32 Firmware Developer, STM32 Firmware Developer, Embedded Systems Engineer, or IoT Firmware Expert who delivers reliable, production-ready solutions, I'd love to discuss your project. Let's build something amazing together! Best Regards, Haresh Sondagar Embedded Systems & IoT Engineer

Building a connected product is hard. It requires expertise across hardware, embedded systems, mobile applications, cloud infrastructure, AI, and the ability to bring all of those pieces together into a production-ready solution. That's where I help. I work with startups, scale-ups, and enterprises to architect and build connected products—from embedded devices and IoT platforms to AI-powered mobile applications and scalable cloud infrastructure. Whether you're building a connected vehicle platform, a medical device, an industrial IoT solution, or the next generation of smart products, I can help take it from concept to production. Over the past 15+ years, I've delivered production software across Connected Vehicles, Telematics, MedTech, Industrial IoT, Transportation, and Enterprise Mobility. Before founding LogiQlink Technologies, I spent over 12 years at Treeline Interactive in San Diego, progressing from Senior Mobile Engineer to Mobile Tech Lead and eventually Head of India Operations. During that time, I worked directly with US startups and enterprises, leading distributed engineering teams and delivering complex connected products used in production. Today, as Founder and Director of LogiQlink Technologies, I continue to help companies build connected products by combining deep technical expertise with hands-on engineering leadership. CORE EXPERTISE Connected Products & IoT • End-to-end connected product development from hardware prototyping to cloud deployment • Embedded Linux, AOSP, and Android Automotive OS (AAOS) • BLE, CAN Bus, MQTT, sensor integration, and industrial communication protocols • Device connectivity, real-time data pipelines, and remote device management platforms AI & Intelligent Systems • AI-powered features for mobile and connected devices • Machine learning integration and on-device inference • Computer Vision, predictive analytics, and intelligent automation Cloud & Backend • AWS and Firebase architecture, deployment, and scaling • REST APIs, GraphQL, backend development, and real-time systems • Event-driven architecture, CI/CD, and scalable cloud infrastructure Mobile Applications • Native Android (Kotlin/Java) and iOS (Swift) • React Native and Flutter • Production mobile applications for connected products, MedTech, transportation, and enterprise platforms HOW I ENGAGE Fractional CTO I help startups define technical strategy, architect scalable platforms, build engineering teams, and make critical technology decisions without the cost of a full-time CTO. Solution Architect I design scalable systems from the ground up—including cloud architecture, hardware-software integration, APIs, and connected product platforms—so your team starts with the right technical foundation. Hands-on Engineer I still enjoy building products. Whether it's a mobile application, embedded firmware, an IoT platform, or a cloud backend, I write clean, maintainable, production-quality code. Engineering Leader I've built and managed distributed engineering teams across the US and India and can help recruit, mentor, and scale engineering organisations for long-term success. WHO I WORK WITH • Startups looking for a technical co-founder or Fractional CTO • Product companies building connected devices and IoT platforms • Automotive, fleet, and mobility technology companies • Medical device and digital health companies • Industrial IoT and enterprise software teams Whether you need a Fractional CTO, Solution Architect, or hands-on engineer, I bring the technical depth to build production-ready systems and the leadership experience to turn ambitious ideas into successful products. If you're building a connected product, I'd love to discuss how I can help.