Gabriel Siedler, Developer in Florianópolis - State of Santa Catarina, Brazil
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Gabriel Siedler

Verified Expert  in Engineering

Software Developer

Florianópolis - State of Santa Catarina, Brazil
Toptal Member Since
October 5, 2016

Gabriel develops UI-rich applications that delight users. With over 10 years of full-stack experience, he creates reliable and easy-to-maintain systems and writes high-quality clean code with top-notch technologies. Gabriel also focuses on modern technologies such as React Redux, React Native, TypeScript, GraphQL, Node.js, Docker, PostgreSQL, and NoSQL databases.


React, D3.js, TypeScript, Redux, Visx, Styled-components, Docker, Axios, Web...
Toptal, LLC
Toptal, LLC
JavaScript, Algorithms




Preferred Environment

Visual Studio Code (VS Code), MacOS

The most amazing... I've built manages a store's inventory using sensors on shelves—alarming the manager with the exact number of items needed and where to add them.

Work Experience

Front-end Specialist

2021 - PRESENT
  • Built an app from the ground up to manage embedded analysis runs and visualize its results, which contain biomolecular information.
  • Engineered sophisticated components and application states, facilitating the dynamic visualization and manipulation of DNA chains and traces.
  • Developed the application's front end as the sole developer, collaborating seamlessly with a team of four back-end developers.
  • Engaged actively with the scrum master, product owner, and team members, contributing to the successful fulfillment of intricate project requirements through effective communication and collaboration.
Technologies: React, D3.js, TypeScript, Redux, Visx, Styled-components, Docker, Axios, Web, Front-end, Front-end Development

Content Creator

2022 - 2023
Toptal, LLC
  • Innovated and developed new technical challenges to enhance the effectiveness of the screening process for prospective candidates.
  • Conducted thorough reviews of front-end documentation, significantly improving recruiter awareness and ensuring precise matching of developers to engagements.
  • Spearheaded various internal projects at Toptal, contributing to the overall efficiency and success of the team.
Technologies: JavaScript

Developer Screener

2022 - 2023
Toptal, LLC
  • Conducted screening interviews to evaluate candidates' skills, ensuring a rigorous selection process for entry into Toptal's esteemed developer team.
  • Coordinated daily interviews efficiently with developers worldwide, fostering a diverse and dynamic talent pool.
  • Contributed actively to weekly meetings to enhance and refine the overall screening and hiring process.
  • Designed and implemented algorithmic challenges and tasks to evaluate candidates' programming skills effectively, ensuring a comprehensive assessment aligned with Toptal's standards.
Technologies: JavaScript, Algorithms

Full-stack Engineer

2022 - 2022
Eran Balter
  • Developed an app based on an existing codebase using React, TypeScript, and Redux. Created the server-side part from scratch using Socket.IO and PostgreSQL.
  • Transformed a regular app into a multiplayer service with real-time interaction.
  • Accomplished MVP requests before the deadline, allowing me to add more features.
  • Created very complex features inside an existing codebase.
Technologies: JavaScript, React, Node.js, Full-stack, Socket.IO, TypeScript, Minimum Viable Product (MVP), Responsive, Full-stack Development

Senior Full-stack Developer

2017 - 2021
AE Studio
  • Worked for great clients like Samsung for more than four years.
  • Contributed to at least 15 projects—most of them with the JavaScript stack.
  • Architected projects and managed developers on several projects.
Technologies: PostgreSQL, Node.js, Angular, Ionic, React, React Native, MongoDB, Styled-components, Heroku, JavaScript, Express.js, TypeScript, HTML5, CSS, CSS3, Sass, SCSS, Next.js, Full-stack, Full-stack Development, Startups, Product Development, APIs, SQL, Web Development, Website Performance, REST, Front-end, Back-end, JSON Web Tokens (JWT), React Hooks, NoSQL, Git, API Development, ES5, REST APIs, Mobile Development, Android, iOS, Technical Leadership, Mobile, Front-end Development, Back-end Development, Electron

Full-stack Developer

2017 - 2017
Shirt App (via AE Studio)
  • Joined the team to help solve bugs due to the app's enormous complexity.
  • Assisted in building the ionic logic that enabled editing HTML shapes on the fly.
  • Helped manage the back-end state to replicate the front-end design, building the final art and shipping it to the selling platform.
Technologies: Node.js, Ionic, Canvas, Shopify

Front-end Developer

2017 - 2017
DVN (via AE Studio)
  • Created the front end from scratch using React, Redux, and the styled-components library.
  • Followed Zeplin files to create the new pages and adapted them to Bootstrap for a fully responsive website.
  • Collaborated with a back-end developer to accomplish tasks.
Technologies: Styled-components, Redux, React

Full-stack Developer

2017 - 2017
  • Enhanced code reliability by organizing and refactoring a significant amount of back-end code.
  • Created complex workflows in React Redux, which were the application's core.
  • Improved the UI/UX dramatically using themes and bundles.
  • Corrected plenty of bugs in the entire application.
Technologies: Redux, React, MongoDB, Node.js, Windows

Full-stack Developer

2017 - 2017
Digital Dojo
  • Played a pivotal role in orchestrating and managing the entire project, ensuring smooth coordination and successful execution.
  • Designed and implemented intricate features innovatively using React/Redux, contributing to the project's growth and functionality.
  • Addressed and resolved bugs proactively, demonstrating a keen eye for detail and a commitment to delivering a polished, error-free final product.
Technologies: MongoDB, Node.js, Redux, React

Full-stack Developer

2017 - 2017
  • Initiated and developed the entire project from inception, showcasing the ability to conceptualize and execute projects from the ground up.
  • Established API and Socket.IO server components, ensuring seamless communication and robust back-end functionality.
  • Crafted an intuitive and responsive front end using React/Redux, enhancing the overall user experience with modern and efficient design practices.
Technologies: Express.js, Socket.IO, MongoDB, Node.js, Redux, React

Front-end Developer

2017 - 2017
  • Developed standalone components using React, contributing to the modular and scalable architecture of the application.
  • Implemented new features within the admin platform, enhancing its capabilities and user functionality.
  • Demonstrated proficiency in troubleshooting and resolving front-end bugs, ensuring a smooth and error-free user experience.
Technologies: CSS3, HTML5, Redux, React

Full-stack Web Developer

2016 - 2017
  • Contributed to developing an analytics app focused on managing store shelf items, enhancing its functionality and user interface.
  • Elevated the UI/UX by introducing a new theme—ensuring full responsiveness, down to 320 pixels, and providing enhanced user feedback.
  • Conducted comprehensive code refactoring, incorporating linters with distinct JavaScript versions for the back and front ends, modularizing code, transitioning to Sass, and optimizing folder structure for improved organization.
  • Expanded browser compatibility by adding support for older versions, ensuring a broader reach and accessibility for users.
  • Integrated the application seamlessly with a data science report service, enhancing its analytical capabilities.
  • Implemented a robust authentication layer, fortifying the app's security measures and ensuring a safer user experience.
Technologies: GitHub, Sass, AngularJS, Redux, React, MongoDB, Express.js, Node.js, Responsive, REST

Full-stack Developer

2016 - 2016
  • Addressed and resolved platform-wide bugs, ensuring the overall stability and reliability of the system.
  • Collaborated in developing standalone React components, contributing to a more modular and maintainable codebase.
  • Implemented comprehensive unit tests for the back end, enhancing code quality and facilitating a more robust and reliable system.
Technologies: Python, React, JavaScript, Jest, Unit Testing

Full-stack Developer

2016 - 2016
Yazabi Predictive, Inc.
  • Completed assigned tasks successfully, ensuring the timely execution of outgoing deliverables.
  • Enhanced the project's overall reliability and performance by systematically identifying and resolving bugs.
  • Prepared the project for release, ensuring it met quality standards and was ready for deployment.
Technologies: MongoDB, HTML5, CSS3, Python, Node.js, React

Front-end Developer

2016 - 2016
  • Collaborated in developing intricate React components, contributing to the project's sophistication and functionality.
  • Translated design concepts from PSD to HTML, ensuring pixel-perfect and responsive implementations.
  • Enhanced overall stability and user experience by systematically addressing and resolving platform-wide bugs.
Technologies: CSS, Redux, React, JavaScript

Full-stack Web Developer

2016 - 2016
  • Developed a soccer statistics app for a local client, showcasing proficiency in creating tailored solutions.
  • Coordinated and led front- and back-end colleagues effectively—ensuring seamless collaboration and project synergy.
  • Engineered the core company manager using the Kohana PHP framework, demonstrating expertise in building robust and scalable web applications.
Technologies: Subversion (SVN), MySQL, Bootstrap, jQuery, Kohana, CodeIgniter, PHP

Full-stack Web Developer

2014 - 2016
  • Contributed to developing one of the world's biggest educational systems, EBS.
  • Created apps for clients like Qualcomm and Tribal.
  • Led the Brazilian team's technical operations for local clients.
Technologies: Docker, GitLab, Jenkins, Sass, Angular, Backbone.js, React, MongoDB, Oracle, Microsoft SQL Server, PostgreSQL, Express.js, Node.js

Full-stack Web Developer | Partner

2012 - 2014
  • Identified prospective customers and negotiated based on the project's complexity.
  • Managed contacts and sales directly with customers.
  • Developed several projects for local customers and small companies.
  • Designed a database using schema tools and implemented it using MySQL.
Technologies: Bootstrap, jQuery, MySQL, CSS, HTML, CodeIgniter, PHP

My Personal Website

A website that I developed on September 16, 2016, and updated in 2017 to use the first versions of Next.js. It is an open-source repository where visitors can find basic information about my work and experience.

AE Studio Website
A Next.js application for AE Studio. I worked with the designer using Figma to build the design with constant feedback. Decided on Next.js because of the need for SEO. After the first loop, I added a headless CMS to allow easier data customization.

Draper Venture Network

A React app with a focus on investments. The client was aware and decided not to make it responsive, and the app was made with React, styled-components, and Node.js. The dashboard and content control is under authentication and cannot be accessed.

Gallant Pet
Joined as the second developer after the first round of implementation took place. Helped make changes in the design, migrating some of the content to a headless CMS and structuring the payment and subscriptions using Stripe.
2008 - 2013

Bachelor's Degree in Computer Science

Federal University of Pelotas - Pelotas, Rio Grande do Sul, Brazil


React Redux, Node.js, React, jQuery, Backbone.js, Socket.IO, MobX, API Development, REST APIs, Stripe API, D3.js


GitLab, GitHub, Jenkins, Adobe Fireworks, Subversion (SVN), Git, Canvas


JavaScript, HTML, CSS, TypeScript, Sass, CSS3, HTML5, PHP, Python, GraphQL, SCSS, SQL, ES5, C, C++


Web, Windows, Linux, Visual Studio Code (VS Code), MacOS, Oracle, Heroku, Docker, Shopify, Android, iOS, Mobile


Responsive, Agile Software Development, Unit Testing, REST, Mobile Development


React Native, Redux, Express.js, AngularJS, Bootstrap, Ionic 3, Angular, CodeIgniter, Kohana, Ionic, Next.js, JSON Web Tokens (JWT), Jest, Electron


MySQL, MongoDB, PostgreSQL, Microsoft SQL Server, NoSQL


Styled-components, User Experience (UX), Full-stack, Full-stack Development, Startups, Product Development, APIs, Web Development, Website Performance, Front-end, Back-end, React Hooks, Machine Learning, Video Compression, Algorithms, Visx, Axios, Minimum Viable Product (MVP), Technical Leadership, Front-end Development, Back-end Development

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