Umer Sheraz.
GH
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Android · 5K+ users · OTP · virtual numbers

SMS Pin Verify

Secure Android app with 5,000+ users — virtual number rentals, OTP delivery via push notifications, global countries, and multi-currency payments (Google Pay, Binance, Bitcoin).

SMS Pin Verify is a secure Android utility for virtual number rentals and OTP delivery via push notifications — with global country selection, multi-currency payments, and real-time verification.

Platform: Android native (Kotlin + Jetpack Compose). I led the complete design and development as a Jetpack Compose Android developer.

Play Store
KotlinJetpack ComposeMVVMClean ArchitectureRetrofitFirebaseGoogle PayHilt

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Overview

At a glance

Platform

Android (Kotlin + Jetpack Compose)

Active users

5,000+

Role

Jetpack Compose Android Developer

Category

OTP / virtual numbers / utility

Overview

Tech stack and tools

CategoryTools / frameworks
LanguageKotlin
UIJetpack Compose
ArchitectureMVVM + Clean Architecture
NetworkingRetrofit + Coroutines
NotificationsFirebase Cloud Messaging (FCM)
PaymentsGoogle Pay, Binance, Bitcoin APIs
SecurityEncryptedSharedPreferences, reCAPTCHA
State managementmutableStateOf, remember, LaunchedEffect
Dependency injectionHilt
TestingCompose Previews, manual QA
DeploymentGoogle Play Console, Firebase Analytics

Case study

Delivery & product depth

My responsibilities

  • Led complete design and development of the secure SMS verification platform as a Jetpack Compose Android developer.
  • Implemented MVVM architecture with Clean Architecture — Repository, ViewModel, and Use Case layers.
  • Built a fully Jetpack Compose UI with dynamic components and responsive layouts.
  • Delivered signup/login with validation (full name, username, email, password, phone, country).
  • Added IP blocking after three failed login attempts and Google reCAPTCHA for bot protection.
  • Implemented forgot-password and secure password-change flows.
  • Integrated dynamic country listing from the backend with nested applications per country for number renting.
  • Delivered OTP reception via push notifications using Firebase Cloud Messaging.
  • Integrated Google Pay (fixed packages), Binance, and Bitcoin (custom amount) payment paths.
  • Built real-time transaction history and balance refresh with safe in-app transaction flows.
  • Shipped profile management — edit profile and secure password change with validation.
  • Handled Play Store deployment, release management, Firebase Crashlytics, and performance tuning.

Deep dive

Feature overview

Architecture and development

  • MVVM with Clean Architecture principles across the Android codebase.
  • Modular structure using Repository, ViewModel, and Use Case layers.
  • Jetpack Compose UI with dynamic components and responsive layouts.
  • State management with mutableStateOf, remember, and LaunchedEffect.

Authentication and security

  • Signup and login with field validation across name, username, email, password, phone, and country.
  • IP blocking after three failed login attempts.
  • Google reCAPTCHA integration for bot protection.
  • Forgot password and password change with validation rules.
  • EncryptedSharedPreferences for sensitive local storage.

Country and application flow

  • Dynamic country listing loaded from backend APIs.
  • Nested applications per country with number renting and purchasing.
  • OTP delivery via Firebase Cloud Messaging push notifications.
  • Real-time verification feedback in the client.

Payment integration

  • Google Pay for fixed package purchases.
  • Binance and Bitcoin APIs for custom-amount top-ups.
  • Real-time transaction history and wallet balance refresh.
  • Safe, secure in-app transaction flow with clear user-visible status.

Profile and publishing

  • Edit profile — full name, username, and country.
  • Secure password change with validation.
  • Play Store deployment and release management.
  • Firebase Crashlytics for crash reporting and analytics.
  • App performance optimization and Compose recomposition control.

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