Vladimir Chernis, Developer in San Diego, CA, United States
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Vladimir Chernis

Android Developer

San Diego, CA, United States

Toptal member since June 14, 2023

Bio

Vlad is an experienced, versatile, T-shaped software engineer who takes a team-first approach to delivering high-quality software for startups and big tech companies. He draws from a broad range of software engineering know-how, starting with a solid computer science foundation from a top 10 university program to gaining over a decade of experience delivering a wide range of successful projects. Vladimir's specialties are native Android apps and scalable back-end services.

Portfolio

Stripe
Android, Accessibility, Kotlin, Coroutines
Tally
Android Development, GitLab CI/CD, Kotlin, Code Review, Unit Testing...
Twitter
Java, Kotlin, Android Development, Model View Intent (MVI), Code Review...

Experience

  • Java - 14 years
  • Android Development - 9 years
  • Android - 9 years
  • Python - 5 years
  • Kotlin - 5 years
  • Web Services - 4 years
  • Django - 3 years
  • Rust - 1 year

Preferred Environment

Android Studio, IntelliJ IDEA, Linux, MacOS, Kotlin, Rust, Python, Java, Xcode, Swift

The most amazing...

...impact I've had on my organization's financial performance is fixing a bug and preventing millions of dollars in revenue loss from a major customer.

Work Experience

Software Engineer

2023 - 2025
Stripe
  • Migrated card issuing services, including a cardholder data environment (CDE), to a next-gen Visa API.
  • Built Android and iOS sample apps for push provisioning Stripe-issued cards supporting Strong Customer Authentication (SCA).
  • Enabled provisioning Stripe-issued Mastercards to Apple Pay with contactless tap.
  • Shipped new features and enhancements around security, accessibility, and observability for terminal card readers and SDKs.
Technologies: Android, Accessibility, Kotlin, Coroutines

Senior Android Engineer

2022 - 2023
Tally
  • Launched several screens with no observable defects in production.
  • Helped track down a CI container issue that was slowing all engineering velocity.
  • Set up a static analysis with CI integration that flagged common pitfalls for the team as we ramped up Compose adoption.
Technologies: Android Development, GitLab CI/CD, Kotlin, Code Review, Unit Testing, Concurrency, Dagger 2, API Design, Jetpack Compose, GitLab, Retrofit 2, Mobile Development, Android, Android Jetpack, Git, Android Studio, Android SDK, Coroutines

Senior Software Engineer

2018 - 2022
Twitter
  • Prevented revenue loss by fixing business-critical brand safety issues.
  • Built a fundamentally new way of dynamically updating the home screen, driving engagement, and unlocking new user experience capabilities.
  • Helped ship a timely hotfix for a business-critical security flaw.
  • Fixed many accessibility issues. Helped create documents and interview questions focused on Google TalkBack.
  • Leveled up our team with mentorship, technical documentation, onboarding of new teammates, tech talks, and team leadership on some projects.
Technologies: Java, Kotlin, Android Development, Model View Intent (MVI), Code Review, Unit Testing, Concurrency, Dagger 2, Accessibility, Jetpack Compose, Mobile Development, Android, Android Jetpack, Git, Android Studio, Android SDK, APIs

Senior Software Developer

2016 - 2018
Grio
  • Built Android apps for clients, including Fitbit and various startups.
  • Helped design, architect review, and test code to ensure quality.
  • Earned raved reviews and contract renewals from Grio's clients.
Technologies: Android Development, Code Review, Unit Testing, Kotlin, Java, Concurrency, Dagger 2, RxJava, Web Services, Retrofit 2, API Development, Mobile Development, Android, Android Jetpack, Git, GitHub, Android Studio, Android SDK

Senior Software Engineer

2014 - 2016
Twitter
  • Overhauled top-level navigation and adopted Material Design.
  • Designed and implemented an integration testing framework for business-critical analytics and observability.
  • Authored and contributed to various design documents and a request for comments (RFCs) for features and enhancements for my team and other engineering teams.
  • Led migration to runtime permission handling throughout the app.
Technologies: Java, Android Development, Unit Testing, Code Review, Concurrency, SQL, Dagger 2, Accessibility, RxJava, Mobile Development, Android, Android Jetpack, Git, Android Studio, Android SDK, Algorithms, APIs

Software Engineer

2013 - 2014
Niantic
  • Improved web app loading performance by 80% through multiple optimizations passed over client and server code.
  • Shipped game mechanics and enhancements on full-stack web and native mobile platforms.
  • Learned and applied geospatial techniques to optimize loading performance across the database, the back end, and the front end.
Technologies: JavaScript, Java, Python, Django, Google App Engine, Code Review, Unit Testing, API Design, Web Services, API Development, Mobile Development, Android, Git, Algorithms

Software Engineer

2012 - 2013
Google
  • Helped ship AI-assisted curation features, a key product differentiator.
  • Assisted in tackling launch-blocking performance issues on certain hardware.
  • Designed and implemented an application-wide photo editing feature.
Technologies: JavaScript, Git, Algorithms

Software Engineer

2010 - 2012
Apple
  • Launched a public-facing web app for gathering software-quality data.
  • Built various interactive dashboards and data visualizations.
  • Built a widely-adopted authentication library for Ruby on Rails.
Technologies: Ruby on Rails (RoR), PHP, MySQL, JavaScript, Web Services, API Development, Git, GitHub, Algorithms, APIs

Software Developer

2009 - 2010
Real Geeks
  • Built map-based real estate search and wore many hats as the number two engineer.
  • Owned every stage of software development for the map-based search project, from design through implementation, deployment, and maintenance.
  • Created the entire stack from Python, Django, and a PostgreSQL back-end to a JavaScript front-end.
Technologies: JavaScript, Google Maps API, MongoDB, SQL, Django, Python, Web Services, API Development, Heroku, Git, Algorithms

Experience

Improved Accessibility on Twitter for Android

After fixing a number of accessibility (a11y) bugs in my team's backlog, I noticed other teams also had large backlogs of longstanding a11y bugs with little progress. I asked around and concluded that even though leadership's guidelines required all features to be accessible to low-vision users, the Android team had lost our only a11y expert and was therefore ill-equipped to tackle a11y bugs beyond basic content descriptions. This explained the mismatch between our feature development guidelines and what the team shipped.

I raised these observations with my manager and proposed my next project. I would proactively share my Twitter a11y expertise and design components for reuse to help make the team's a11y goals more attainable by lowering the barrier to entry for engineers with no a11y background to evaluate, design, and implement accessible features. Spreading my a11y expertise through code and design reviews, shipping reusable components, and recipe-book-style documentation, enabled other Android engineers to improve or unlock inaccessible features for the first time for screen reader users.

This work enabled feature teams across the app to comply with a11y requirements and avoid leaving our low-vision customers in the dark.

Education

2005 - 2009

Bachelor's Degree in Computer Science

University of Texas at Austin - Austin, TX, United States

Skills

Libraries/APIs

API Development, Retrofit 2, Google Maps API, RxJava, Stripe API

Tools

Android Studio, Android Jetpack, Git, GitLab CI/CD, GitLab, GitHub, Xcode

Languages

Kotlin, Python, Java, JavaScript, Ruby, SQL, Rust, TypeScript, PHP, Swift, Go

Frameworks

Android SDK, Dagger 2, Django, Ruby on Rails (RoR), iOS SDK

Paradigms

Mobile Development, Unit Testing, Model View Intent (MVI)

Platforms

Android, Google App Engine, Heroku, iOS

Storage

MySQL, MongoDB

Other

Android Development, APIs, Web Services, Jetpack Compose, Concurrency, Code Review, Accessibility, Algorithms, Coroutines, API Design, Sorbet, Compilers, Data Structures, Operating Systems

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