Nikita Teplyakov, Developer in Seville, Spain
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Nikita Teplyakov

Software Developer

Seville, Spain

Toptal member since August 31, 2022

Expertise
JSONREST APIAndroidKotlinFlutterDartAlgorithmsCode ReviewJavaGitSQLFirebaseDockerScala
Bio

Nikita is an experienced mobile developer with 10+ years of hands-on work building high-quality Android applications and 3 years of cross-platform development using Flutter and Kotlin Multiplatform. He follows SOLID principles and uses Clean Architecture and MVVM to create scalable and maintainable apps. Nikita is passionate about discovering new technologies, mentoring other developers, and building intuitive mobile experiences that users love.

Portfolio

B2Broker
Android, Jetpack Compose, Hilt, Coroutines, Retrofit 2, Amplitude, MockK...
Oz Forensics
Android, Flutter, Coroutines, Kotlin, Firebase, GitLab, MockK
Fastdev
Android, Kotlin, Flutter, Dart, Continuous Delivery (CD)...

Experience

  • Mobile App Development - 10 years
  • Android - 8 years
  • Algorithms - 6 years
  • Android Jetpack - 5 years
  • Kotlin - 5 years
  • Flutter - 4 years
  • Model View ViewModel (MVVM) - 4 years
  • Kotlin Multiplatform Mobile (KMM) - 2 years

Preferred Environment

Android, Flutter, Kotlin, Android Jetpack, Model View ViewModel (MVVM), Git, Algorithms, Kotlin Multiplatform, Kotlin Multiplatform Mobile (KMM)

The most amazing...

...thing I've developed is a social app that was ranked third in Google's Play Store and received 500,000 downloads in the first six months after its release.

Work Experience

Android Developer

2024 - PRESENT
B2Broker
  • Implemented dynamic form (BDUI) mechanics for deposit and withdrawal flows.
  • Implemented new features and fixed bugs for the white-label broker application.
  • Implemented a new design system and migrated the existing app to the design system.
  • Reimplemented the existing app on the Kotlin multiplatform stack.
  • Integrated Claude Code to implement new components to speed up implementation.
Technologies: Android, Jetpack Compose, Hilt, Coroutines, Retrofit 2, Amplitude, MockK, Kotlin Multiplatform, Kotlin Multiplatform Mobile (KMM)

Android/Flutter Developer

2023 - 2024
Oz Forensics
  • Analyzed, mitigated, and resolved security issues using DexGuard, SSL pinning, emulator and root detection, and native code through the NDK.
  • Developed and integrated robust licensing mechanisms.
  • Migrated legacy Camera2 integration to CameraX for streamlined camera functionality.
  • Refactored and optimized an existing Flutter plugin to align with the latest coding standards.
  • Maintained plugin compatibility across Android and iOS by extending features to mirror native SDK updates.
Technologies: Android, Flutter, Coroutines, Kotlin, Firebase, GitLab, MockK

Android and Flutter Developer

2021 - 2022
Fastdev
  • Refactored a legacy application to new technologies.
  • Estimated and implemented new features—from UI flows to geolocation‑based order tracking—per Figma designs.
  • Used Firebase to find new bugs and Jira to track existing bugs.
  • Wrote an open source Flutter plugin to cover some features.
Technologies: Android, Kotlin, Flutter, Dart, Continuous Delivery (CD), Continuous Integration (CI), Android Jetpack, Model View ViewModel (MVVM), RoomDB, REST, Code Review, Source Code Review, Git, GitLab, GitLab CI/CD, Retrofit 2, Hilt, Retrofit, Navigation, JSON, Mobile App Development, Startups, In-app Purchases, WebSockets, Android Studio, Firebase, Gradle, SQL, SonarQube, Geolocation, Analytics, SQLite, Material 2, Jira

Flutter Developer

2020 - 2021
Auslogics Software Pty Ltd
  • Completed and refined features inherited from a previous developer to ensure full functionality.
  • Implemented new training modules and user interface enhancements.
  • Managed App Store submission process and release pipeline.
  • Monitored production, diagnosed issues, and resolved bugs for optimal user experience.
Technologies: Flutter, Dart, In-app Purchases, Firebase, Git, GitLab, Jira, JSON, Mobile App Development, Android, Android Studio, Gradle, Analytics

Android Developer

2019 - 2020
Distillery
  • Designed and executed A/B tests with custom frameworks, Firebase, Amplitude, and Mixpanel to optimize user flows.
  • Instrumented event tracking for behavioral analysis.
  • Conducted code reviews and migrated Java codebases to Kotlin.
  • Modernized a legacy Java app to Android Jetpack (MVVM, Room, and WorkManager) and Dagger 2.
  • Integrated Bluetooth device data collection, back-end synchronization, and real‑time patient feedback.
  • Mentored and consulted a fellow developer, led API design discussions, and reviewed code for quality and standards.
Technologies: Android, Kotlin, Git, GitHub, Code Review, Source Code Review, Geolocation, Model View ViewModel (MVVM), Android Jetpack, REST, Jira, Hilt, Retrofit, Retrofit 2, JSON, Mobile App Development, Java, Startups, Android Studio, Firebase, Mixpanel, Gradle, SQL, RoomDB, Analytics, SQLite, Material 2

Android Developer

2018 - 2019
Oktos
  • Maintained and enhanced a secure messenger featuring end‑to‑end encryption and integrated cryptocurrency support for E2E messanger.
  • Designed and developed new features from scratch, ensuring seamless encrypted communication.
  • Participated in sprint planning and task decomposition to drive iterative delivery.
  • Conducted code reviews to enforce best practices and maintain code quality.
  • Migrated core services from Scala to Kotlin for a unified codebase and improved maintainability.
Technologies: Android, Cryptography, WebSockets, Scala, Code Review, Source Code Review, Bitbucket, Git, Firebase, Analytics, SQLite, Geolocation, Jira, JSON, Mobile App Development, Kotlin, Android Jetpack, Retrofit 2, Android Studio, Gradle, SQL, REST, Material 2, Live Chat, Retrofit, Dagger 2

Android Developer

2017 - 2018
Pixel Point
  • Developed Android and iOS applications from scratch for seamless fiat-to-crypto and crypto-to-fiat trading.
  • Collaborated with designers and product managers to refine UI/UX and define feature requirements.
  • Prepared and submitted Android and iOS apps for release, handling packaging, compliance, and store workflows.
Technologies: Android, iOS, Swift, Java, Git, GitHub, WebSockets, REST, Trello, JSON, Mobile App Development, Android Jetpack, Model View ViewModel (MVVM), Retrofit 2, Startups, Android Studio, Firebase, Gradle, SQL, RoomDB, SQLite, Material 2, Retrofit, Dagger 2

Android Developer

2015 - 2016
HelloBaby, Inc
  • Architected and developed a secure journaling app for children, enabling private entries with optional family sharing.
  • Led a teammate through feature development, mentoring on best practices, and workflows.
  • Conducted thorough code reviews to maintain quality and consistency.
  • Implemented a custom in‑app camera module for seamless photo journaling.
  • Prepared and submitted the application for release, handling packaging, and store compliance checks.
Technologies: Android, Java, Git, GitHub, SQLite, Material 2, REST, Trello, JSON, Mobile App Development, Android Jetpack, Model View ViewModel (MVVM), Retrofit 2, Startups, In-app Purchases, Android Studio, Firebase, Gradle, SQL, RoomDB, Geolocation, Retrofit, Dagger 2

Android Developer

2014 - 2015
MyLove
  • Architected and built a dating app from scratch, defining core features and user flows.
  • Prepared the application for release, including packaging, deployment pipeline set up, and store submissions.
  • Launched the new application on the Google Play Store, resulting in over 500.000 downloads in the first six months.
  • Monitored production performance and promptly diagnosed and resolved bugs to ensure a smooth user experience to archive 99.9% crash-free sessions.
Technologies: Android, Java, Git, WebSockets, Live Chat, Geolocation, JSON, Mobile App Development, In-app Purchases, Android Studio, Gradle, REST, SQLite

Scala Developer

2013 - 2014
Tooeezzy
  • Refactored a legacy PHP back end to a Scala and Akka back end.
  • Revamped a legacy MySQL database and queries to NoSQL Mongo database.
  • Increased back-end performance from about 2 rps to 12,000 rps.
Technologies: Scala, Akka, MongoDB, JSON, Git, REST

Experience

Android Dating Application

https://play.google.com/store/apps/details?id=ru.mylove.dating&hl=en&gl=US
Android application that connects single people. It was in the top three by searching the keyword dating in Russia. The app uses back-end API to show data and WebSockets to chat. The application got 500.000 downloads within six months after the release date. According to crashalytics reports, it had 99.9% crash-free sessions.

Education

2004 - 2009

Master's Degree in Computer Science

Perm State Technical University - Perm, Russia

Certifications

DECEMBER 2013 - PRESENT

Principles of Reactive Programming

Coursera

SEPTEMBER 2013 - PRESENT

Startup Engineering

Coursera

NOVEMBER 2012 - PRESENT

Functional Programming Principles in Scala

Coursera

MARCH 2012 - PRESENT

Programming Languages

Coursera

Skills

Libraries/APIs

Retrofit 2, Retrofit, REST APIs, Material 2, MockK

Tools

Android Jetpack, Android Studio, Git, Gradle, SonarQube, GitLab, GitLab CI/CD, GitHub, Jira, Bitbucket, Trello

Languages

Dart, Kotlin, Java, Scala, SQL, Swift

Frameworks

Flutter, Dagger 2, Akka

Paradigms

Model View ViewModel (MVVM), Continuous Integration (CI), Continuous Delivery (CD), REST

Platforms

Android, Firebase, Mixpanel, Docker, iOS

Storage

JSON, RoomDB, SQLite, MongoDB, PostgreSQL

Other

Mobile App Development, Analytics, Hilt, Jetpack Compose, Kotlin Multiplatform, Kotlin Multiplatform Mobile (KMM), APIs, Computer Science, Programming Languages, Algorithms, Startups, In-app Purchases, Cryptography, WebSockets, Code Review, Source Code Review, Geolocation, Navigation, Reactive Streams, Live Chat, Coroutines, Amplitude

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