Iuri is available for hire
Hire IuriIuri Alexandre Cernov de Oliveira Barbosa
Verified Expert in Engineering
Full-stack Developer
Location
São José dos Campos - State of São Paulo, Brazil
Toptal Member Since
September 20, 2017
Iuri Cernov is the type of developer with a linear thought process for solving problems who divides his work into small parts and does everything possible to ensure the quality of the final product. He is also passionate about mobile apps and new technologies, having experience in native Android and iOS, and React Native frameworks. The full stack with JavaScript is also part of his experience.
Portfolio
Terapia de Bolso
AWS DevOps, JavaScript, TypeScript, Django, Python, Angular...
Citizen
Android, Mobile, Product Management, Google Material Design, ReactiveX...
Cernov Apps
React Native, Android, iOS, Web, Google Material Design, ReactiveX, React...
Experience
Availability
Part-time
Preferred Environment
Kotlin, Android, React, React Native, JavaScript
The most amazing...
...thing I've built was an aviation website that received a large number of visits and was mentioned in a famous national magazine.
Work Experience
CTO
2023 - 2023
Terapia de Bolso
- Handled the full migration of a PHP website to a microservices architecture.
- Implemented IaaC using Terraform and the serverless framework.
- Managed the rollout of the new website and monitored the transition.
- Prepared a team of developers to increase development speed.
Technologies: AWS DevOps, JavaScript, TypeScript, Django, Python, Angular, Technical Leadership, Payment APIs, Microservices, APIs, REST APIs, Full-stack, SQL, PostgreSQL, Software Development Management, Engineering, CTO, Architecture, Amazon Web Services (AWS), Amazon EC2, RDS, GitHub, RxJava 2, Infrastructure as Code (IaC), DevOps, MySQL, Amazon RDS, REST, Back-end, Back-end Development, Unit Testing, Full-stack Development, CSS, HTML, Front-end, DOM, Virtual DOM, CI/CD Pipelines, JSON, API Integration, HTML5, User Interface (UI), Push Notifications, Mobile Development, WebRTC, Web Development
Senior Android Engineer
2022 - 2023
Citizen
- Rewrote the home screen of the Android app with a new layout to increase user engagement by exploring incidents.
- Assisted the team in implementing experiments controlled by feature configurations: one of the experiments was a premium upsell in feed.
- Led the technical work to implement a new incident details screen from scratch by writing eng spec, assisting iOS and Android developers, communicating with the product, and managing the rollout.
- Led the technical work to implement the location permission upsell project, a set of features to incentive users to enable their location and get more value from the app.
- Helped on infrastructure projects such as rewriting screens to Jetpack Compose; conversion from ReactiveX to coroutines; reviewing multi-threading issues; migrating components to Hilt; and enforcing high standards of code quality.
Technologies: Android, Mobile, Product Management, Google Material Design, ReactiveX, Coroutines, Dagger, Jetpack Compose, Git, Technical Leadership, Android SDK, Video Streaming, Figma, APIs, Mobile App Development, Firebase, REST APIs, Engineering, Architecture, Mobile Architecture, GitHub, Mobile App Design, Model View ViewModel (MVVM), Android Studio, RxJava 2, REST, Unit Testing, Mobile Apps, ECMAScript (ES6), CI/CD Pipelines, JSON, API Integration, Android Jetpack, User Interface (UI), Push Notifications, Mobile Development
Founder and CEO
2019 - 2021
Cernov Apps
- Provided leadership of the company. I hired interns and full-time employees with interviews and programming tests, trained interns for React Native and best practices, and managed most projects, delegating some of them.
- Sold the services to clients. Most of the services usually sold were to create a mobile app end to end for companies that had only a web dashboard and available APIs.
- Created the Delfos app from scratch (https://apps.apple.com/br/app/delfos-im/id1466294332) using React Native, GraphQL APIs, TypeScript, and WebSockets for real time.
- Created the PowerHub app from scratch (https://apps.apple.com/br/app/powerhub/id1492166180) using React Native, GraphQL APIs, and TypeScript.
- Created the Way2 app from scratch (https://apps.apple.com/us/app/way2-usinas-de-energia/id1512777054) using: React Native, REST APIs, and TypeScript.
- Created the Selaz app from scratch using: React Native, REST APIs, and TypeScript. This is a medical app for doctors and patients to manage bone deformity treatments with an external fixator; however, the app was not published as the client decided so.
Technologies: React Native, Android, iOS, Web, Google Material Design, ReactiveX, React, JavaScript, Node.js, Mobile, Coroutines, TypeScript, Git, Technical Leadership, Figma, APIs, Expo, Mobile App Development, Firebase, REST APIs, Full-stack, SQL, PostgreSQL, Software Development Management, B2B, Engineering, Architecture, Bluetooth LE, Bluetooth, Mobile Architecture, Amazon Web Services (AWS), Amazon EC2, RDS, GitHub, Mobile App Design, Model View ViewModel (MVVM), Android Studio, Redux, Amazon RDS, REST, Back-end, Back-end Development, Unit Testing, CSS, HTML, Front-end, DOM, Virtual DOM, Mobile Apps, ECMAScript (ES6), CI/CD Pipelines, JSON, API Integration, HTML5, User Interface (UI), Push Notifications, Mobile Development, Web Development
Senior Android Engineer | Full-stack Developer
2019 - 2021
ClassDojo
- Contributed to the infrastructure of an Android codebase: Java > Kotlin; manual injection > Dagger > Dagger/Hilt. I also implemented a strict pattern of MVVM in most features.
- Rewrote feed and chat features with best practices and high code-quality guidelines.
- Participated in the school chat feature as a full-stack developer from scratch.
- Led hired contractors to refactor the core features of the app.
- Implemented multiple pages worksheets in the Android app, with big challenges: automatic saving, new drawing tools, and saving serialized data so the student can continue editing later.
- Suggested and implemented In-App Review for Android (a very simple feature, but it increased the average review from less than 3.5 to 4.8).
Technologies: Java, Android, Kotlin, React, Node.js, AWS DevOps, Google Material Design, ReactiveX, JavaScript, Mobile, Coroutines, Dagger, Full-stack Development, TypeScript, Git, Docker, Android SDK, Figma, APIs, Mobile App Development, Firebase, REST APIs, Full-stack, Engineering, Architecture, Mobile Architecture, Amazon Web Services (AWS), GitHub, Mobile App Design, Model View ViewModel (MVVM), Android Studio, RxJava 2, Infrastructure as Code (IaC), DevOps, MySQL, Redux, Amazon RDS, REST, Back-end, Cypress, Unit Testing, CSS, HTML, Front-end, DOM, Virtual DOM, Mobile Apps, ECMAScript (ES6), CI/CD Pipelines, JSON, API Integration, Android Jetpack, User Interface (UI), Internationalization, Push Notifications, Mobile Development
Android/iOS Developer
2016 - 2019
Buson
- Improved the development process for Android and iOS apps.
- Worked on the full redesign of both apps and managed the transition.
- Used Objective-C and Swift to develop new iOS app features.
- Used analytics data for monitoring releases, bug fixes, and general usage statistics.
- Improved the user experience: deep link, remote configuration, and A/B tests.
- Converted most of the codebase from Objetive-C to Swift.
- Developed the "Buson Venda Embarcada" app from scratch: the app allows bus drivers to sell tickets directly to passengers. The app had to work offline, so there were big challenges to synchronizing with servers and performing in-app XML signatures.
Technologies: Swift, Objective-C, iOS, Kotlin, Java, Android, Google Material Design, ReactiveX, Mobile, React Native, Coroutines, Dagger, Git, Android SDK, Figma, APIs, Mobile App Development, Firebase, REST APIs, B2B, Engineering, Architecture, Bluetooth LE, Bluetooth, Mobile Architecture, GitHub, Mobile App Design, Android Studio, RxJava 2, REST, Unit Testing, Mobile Apps, ECMAScript (ES6), CI/CD Pipelines, JSON, API Integration, User Interface (UI), Push Notifications, Mobile Development
Flight Operations Engineer
2015 - 2016
Embraer
- Improved the algorithm for generating performance tables for the pilot's manual.
- Improved the quality of the iPad app for operational performance calculation for pilots as a tester.
- Developed various types of customer service software for desktops.
- Provided internal training sessions for employees in the area of flight operations engineering.
- Participated in some quality test flights by doing performance calculations.
Technologies: Java, Object-oriented Programming (OOP), ReactiveX, Mobile, Git, APIs, REST APIs, SQL, Engineering, REST, JSON, API Integration, User Interface (UI)
Experience
Citizen Android App
https://citizen.comAn app that provides real-time safety alerts, videos of incidents happening near users, and trained agent service.
I rewrote the home screen of the Android app with a new layout to increase user engagement by exploring incidents. I also led the technical work to implement a new incident details screen and location permission upsell. I worked on infrastructure projects such as rewriting screens to Jetpack Compose; converting ReactiveX to coroutines; reviewing multithreading issues; migrating components to Hilt; and enforcing high code quality standards.
I rewrote the home screen of the Android app with a new layout to increase user engagement by exploring incidents. I also led the technical work to implement a new incident details screen and location permission upsell. I worked on infrastructure projects such as rewriting screens to Jetpack Compose; converting ReactiveX to coroutines; reviewing multithreading issues; migrating components to Hilt; and enforcing high code quality standards.
ClassDojo Android App
https://play.google.com/store/apps/details?id=com.classdojo.androidClassDojo is an app that connects teachers, parents, and students. Some key features of the app include the feed where teachers can publish, the interaction between parents and students, chats between teachers and parents, and homework.
I rewrote feed and chat features with best practices and high code-quality guidelines. I also implemented multiple pages worksheets in the Android app, with big challenges: automatic saving, new drawing tools, and saving serialized data so that the student can continue editing later. The infrastructure I worked on: Java > Kotlin; manual injection > Dagger > Dagger/Hilt. I also implemented a strict pattern of MVVM in most features.
I rewrote feed and chat features with best practices and high code-quality guidelines. I also implemented multiple pages worksheets in the Android app, with big challenges: automatic saving, new drawing tools, and saving serialized data so that the student can continue editing later. The infrastructure I worked on: Java > Kotlin; manual injection > Dagger > Dagger/Hilt. I also implemented a strict pattern of MVVM in most features.
Delfos IM Android and iOS Apps
https://apps.apple.com/br/app/delfos-im/id1466294332This app is a mobile version of the Delfos IM web dashboard where clients can monitor and get insights on power generation.
I started the app from scratch and wrote the core features using React Native. I also published Android and iOS apps, leading the Cernov Apps team to implement improvements.
I started the app from scratch and wrote the core features using React Native. I also published Android and iOS apps, leading the Cernov Apps team to implement improvements.
PowerHub Android and iOS Apps
https://apps.apple.com/br/app/powerhub/id1492166180A B2B app for industries and big energy consumers to have visibility on energy consumption.
I started the app from scratch and wrote the core features using React Native. I published Android and iOS apps. I also led the Cernov Apps team to implement improvements.
I started the app from scratch and wrote the core features using React Native. I published Android and iOS apps. I also led the Cernov Apps team to implement improvements.
Way2 Android and iOS Apps
https://apps.apple.com/us/app/way2-usinas-de-energia/id1512777054A B2B app to monitor energy generation on power plants.
I started the app from scratch and wrote the core features using React Native. I also published Android and iOS apps, leading the Cernov Apps team to implement improvements.
I started the app from scratch and wrote the core features using React Native. I also published Android and iOS apps, leading the Cernov Apps team to implement improvements.
Buson Android App
https://play.google.com/store/apps/details?id=com.guichevirtual.androidBuson is an online solution for selling bus tickets in Brazil. The Android app has the following features: buy tickets with direct integration with bus companies' systems; management of bought tickets; seat selection; and boarding with QR code.
Some contributions of mine include full redesign, migration to Kotlin, and implementation of new features.
Some contributions of mine include full redesign, migration to Kotlin, and implementation of new features.
Buson iOS App
Buson is an online solution for selling bus tickets in Brazil. The iOS app has the following features: buy tickets with direct integration with bus companies' systems; management of bought tickets; seat selection; and boarding with QR code.
Some contributions of mine were the full redesign, migration to Swift, and implementation of new features.
Some contributions of mine were the full redesign, migration to Swift, and implementation of new features.
Buson Venda Embarcada
The Buson Venda Embarcada is a B2B app for bus drivers to sell bus tickets directly to passengers.
I started the development of the app from scratch. I also worked on offline synchronization: the sale must happen offline, and the app synchronizes with the API when back online. I integrated the app with the Brazilian Revenue Service (Receita Federal), requiring XML signatures and following strict specifications on the sale communication protocol. The app is also integrated with a thermal printer so the passenger can have a ticket copy. I also worked on the integration of the app with credit card machines.
I started the development of the app from scratch. I also worked on offline synchronization: the sale must happen offline, and the app synchronizes with the API when back online. I integrated the app with the Brazilian Revenue Service (Receita Federal), requiring XML signatures and following strict specifications on the sale communication protocol. The app is also integrated with a thermal printer so the passenger can have a ticket copy. I also worked on the integration of the app with credit card machines.
Skills
Languages
Kotlin, JavaScript, TypeScript, SQL, HTML, ECMAScript (ES6), Swift, Java, HTML5, Objective-C, Python, CSS
Frameworks
React Native, Android SDK, Redux, Dagger, Django, Angular, Cypress
Libraries/APIs
ReactiveX, REST APIs, RxJava 2, React, Node.js, WebRTC
Tools
GitHub, Android Studio, Android Jetpack, Git, Gradle, Terraform, Figma, Expo
Paradigms
Model View ViewModel (MVVM), REST, Unit Testing, Mobile Development, B2B, Mobile App Design, Object-oriented Programming (OOP), Microservices, DevOps
Platforms
Firebase, Android, iOS, Amazon EC2, Mobile, Web, Docker, Amazon Web Services (AWS), Bluetooth LE
Storage
JSON, MySQL, RoomDB, PostgreSQL
Other
APIs, Mobile App Development, Engineering, Architecture, Mobile Architecture, Mobile Apps, API Integration, User Interface (UI), Jetpack Compose, Coroutines, Video Streaming, Software Development Management, Back-end, Back-end Development, Full-stack Development, Front-end, CI/CD Pipelines, Proof of Concept (POC), Internationalization, Push Notifications, Google Material Design, Aeronautical Engineering, AWS DevOps, Product Management, Full-stack, Technical Leadership, Payment APIs, CTO, Bluetooth, RDS, Infrastructure as Code (IaC), Amazon RDS, DOM, Virtual DOM, Web Development
Education
2013 - 2014
Exchange Student in Aeronautical Engineering
ENSICA | École Nationale Supérieure d'Ingenieurs de Constructions Aéronautiques - Toulouse, France
2010 - 2014
Bachelor's Degree in Aeronautical Engineering
ITA | Instituto Tecnológico de Aeronáutica - São José dos Campos, SP, Brazil
Collaboration That Works
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
1
Share your needs
Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2
Choose your talent
Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3
Start your risk-free talent trial
Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.
Top talent is in high demand.
Start hiring