Sacha Leonel Lifszyc, Developer in Buenos Aires, Argentina
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Sacha Leonel Lifszyc

Verified Expert  in Engineering

Bio

With over a decade of experience in the software development industry, Sacha is an experienced senior front-end engineer specializing in React, TypeScript, and GraphQL. His 4-year tenure at Toptal's core team highlights how his exceptional technical leadership and dedication have helped decrease thousands of talents activation time and boost scheduled interviews conversion rate. Sacha's versatile portfolio demonstrates his ability to enhance projects with expert precision.

Portfolio

Toptal
React, TypeScript, GraphQL, GraphQL Code Generator, Apollo Client...
Digital House
Education, Teaching, PHP, Laravel, MySQL, Apache, JavaScript, Web Development
Restorando
React, JavaScript, TypeScript, GraphQL, Styled-components, Amplitude...

Experience

  • JavaScript - 10 years
  • Front-end - 10 years
  • React - 7 years
  • GraphQL - 7 years
  • TypeScript - 7 years
  • Storybook - 4 years
  • Node.js - 4 years
  • Tailwind CSS - 1 year

Availability

Part-time

Preferred Environment

MacOS, Visual Studio Code (VS Code), Chrome

The most amazing...

...products I've worked on are web applications for Toptal's core team that helped accelerate talent activation and candidate introduction processes.

Work Experience

Principal Front-end Engineer

2020 - 2024
Toptal
  • Streamlined the profile activation process for thousands of talents, decreasing their time to market within the talent network by more than 35%.
  • Enhanced the talent presentation process to clients by developing a web application from scratch that highlights talent profiles' most relevant parts for specific job descriptions, improving scheduled interview conversion rates by 5%.
  • Contributed to the development of 10+ robust UI components for public use, featuring excellent component APIs that enhanced functionality and user experience.
  • Headed over 15 initiatives that seamlessly integrated new features into web applications, consistently delivering high-quality enhancements.
  • Introduced and advocated for component-driven development across multiple teams, significantly improving code maintainability and readability and the engineers' overall happiness.
  • Promoted from senior to principal front-end engineer in recognition of outstanding leadership and technical contributions to the company.
  • Trained a team on React Final Forms, reducing development time for form-related features, enhancing overall productivity, and strengthening team collaboration, communication, and trust.
  • Led the development of a new UI component that showcased the overlapping working hours between a client and a talent in two different time zones, which received excellent feedback from our clients and matchers.
  • Reorganized the Storybook documentation and standardized page sections, simplifying the developer experience and reducing development time.
  • Participated in the front-end advisory board, engaging in strategic discussions that had a significant, company-wide impact on technology and application design decisions.
Technologies: React, TypeScript, GraphQL, GraphQL Code Generator, Apollo Client, React Final Form, FinalForms, Technical SEO, Web Accessibility, Styled-components, Tailwind CSS, Jest, React Testing Library, Cypress, Playwright, Storybook, HTML, CSS, Design Systems, GitHub Actions, GitHub, Git, Scrum, Jira, Datadog, Sentry, Google Analytics, Google Analytics 4, Monorepos, NPM, Yarn, Visual Studio Code (VS Code), Chrome, APIs, Moment.js, Search Engine Optimization (SEO), Electron, Zod, Leadership, Technical Leadership, Front-end, Accessibility, Web Development, Material UI, REST APIs, API Integration

Full-stack Bootcamp Instructor

2019 - 2020
Digital House
  • Led two full-stack software development courses at a top tech institute in Buenos Aires.
  • Instructed over 40 students with little to no prior software development experience on building web applications through practical examples.
  • Addressed student questions and assisted in correcting practical essays.
Technologies: Education, Teaching, PHP, Laravel, MySQL, Apache, JavaScript, Web Development

Senior Front-end Lead Engineer

2017 - 2019
Restorando
  • Directed the web application migration from a Rails monolith to a React-based architecture, significantly modernizing the platform and enhancing performance.
  • Developed a new photo carousel for displaying restaurant pictures, enhancing the platform's visual appeal and user engagement.
  • Collaborated with the search engine optimization (SEO) department from MercadoLibre, validating a strategic roadmap that improved SEO positioning and organic traffic.
  • Initiated and executed a 360-degree photography project for several restaurants, incorporating immersive visuals into restaurant pages as an experimental feature to enhance user experience.
  • Improved conversion rate by 2% for selected Colombian restaurants through a personal initiative to enhance their photographic content during a business trip.
  • Created a special San Valentine's Day landing page and advertisement featuring a curated selection of restaurants, which included personal involvement in video production and website design.
Technologies: React, JavaScript, TypeScript, GraphQL, Styled-components, Amplitude, Search Engine Optimization (SEO), Redux, Jest, Storybook, Node.js, Visual Studio Code (VS Code), Chrome, APIs, Technical SEO, Leadership, Front-end, Web Development, Accessibility, REST APIs, Full-stack Development, API Integration

Senior Full-stack Lead Engineer

2013 - 2016
Democracia en Red
  • Developed key features for our main web application, like sign-in, voting, and commenting for a civic engagement platform.
  • Built new functionalities, including likes, dislikes, and replies, enhancing user interaction.
  • Selected by Y Combinator for their inaugural batch of nonprofit organizations, recognizing our innovative approach to civic engagement.
  • Deployed tailored instances for local congresses and municipal departments, customizing user experiences to meet specific needs.
  • Presented software at the Buenos Aires City Congress, demonstrating real-world legislative application.
  • Enabled global use with unexpected forks, including a Turkish version of the platform.
  • Collaborated with European NGOs in Berlin to enhance global citizen participation.
  • Utilized Segment.io and Google Analytics to refine user engagement strategies.
  • Guided the DemocracyOS project as senior full-stack lead engineer, overseeing expansion and adaptation.
  • Deployed and maintained the platform on Heroku, ensuring smooth operation and scalability.
Technologies: Node.js, NPM, JavaScript, CSS, Browserify, MongoDB, Express.js, Databases, Google Analytics, Segment.io, Open Source, Heroku, Leadership, APIs, Web Development, Full-stack, Object-oriented Databases, Accessibility, REST APIs, Full-stack Development, API Integration

Experience

Toptal Public Pages UI Components Library

Implemented a design system that exposes reusable components and general utility functions built with React, TypeScript, and Tailwind CSS to release superior digital products quickly and consistently.

Job-specific Resume Page

Played a pivotal role in developing a dynamic, responsive web page designed to effectively present candidate profiles to clients tailored to specific job requirements. I was a senior front-end engineer on this project. It was built from scratch using React, TypeScript, GraphQL, and a suite of modern development tools, including styled-components and Apollo Client, which focused on enhancing matchmaking by highlighting relevant candidate details.

A key challenge was creating an interactive UI component displaying overlapping working hours between clients and talents across different time zones. My leadership in designing and implementing this feature was crucial, involving resolving complex product issues related to time overlap visualizations. This component was highly praised for its interactivity and effectiveness, significantly contributing to its success.

The redesigned, responsive page improved the user experience and increased the conversion rate of scheduled interviews, demonstrating a substantial enhancement in how talents were introduced to potential clients.

Talent Profile Application

As a senior front-end engineer, I contributed to developing a single-page application designed for talent and staff profile management within Toptal's talent network. Utilizing technologies like React, TypeScript, and GraphQL, I created and led the development of multiple features, enhancing user experience and reducing profile completion times. I also introduced component-driven development to our team, simplifying our codebase and improving maintainability. This key improvement contributed to my promotion to principal engineer and marked a significant milestone in my career.

Talent Testing Platform

Played a crucial role in developing two web-based applications—one for staff (administrators) and another for applicants (end users)—designed to facilitate the creation and management of online tests and exams. Utilizing a technology stack that included React, TypeScript, GraphQL, and Apollo Client, I worked on significant enhancements that improved the functionality and user experience.

My key contributions included implementing a feature that allowed for grouping questions into sections, which could be sorted, renamed, and organized as needed. Additionally, I developed an events timeline that recorded and displayed various activities during a candidate's test session. This timeline was crucial for monitoring and flagging suspicious activity, enhancing the integrity and oversight capabilities of the testing platform for administrators.

Talent Desktop Application

Contributed to developing an Electron desktop application for macOS, designed to provide talents with real-time notifications on new job postings and updates during my brief 3-week tenure on the project. I utilized React, TypeScript, GraphQL, and Apollo Client to implement a feature that displayed a list of job applications, added a browser shortcut to the Talent Portal, and developed a functionality for talents to toggle their availability status manually.

These enhancements improved the application's functionality and user interaction, enabling talents to adjust profile settings and providing direct links to essential web-based resources. Thus, the process for talents to act swiftly on potential job opportunities was streamlined.

Restorando Web Application

Worked on the transformation of Restorando, which was subsequently acquired by The Fork. As a senior front-end engineer initially and later as a technical leader, my contributions centered on migrating the legacy Ruby on Rails and Backbone monolith to a modern React-based web application.

This strategic overhaul modernized the technology stack and significantly enhanced the user interface and user experience. The successful migration led to more agile development processes and a robust platform capable of handling increased user traffic and complex functionalities.

DemocracyOS

https://github.com/democracyos/democracyos
DemocracyOS is an innovative open-source platform that enhances civic engagement by enabling citizens to vote on and discuss legislative proposals. It was developed to bridge the gap between governments and their constituents and empower users to understand, debate, and influence public policies directly from their devices. DemocracyOS has been adopted worldwide by various governmental and non-governmental organizations to promote transparency, foster democratic participation, and facilitate informed discussions on a wide range of issues affecting communities.

CivicStack

https://github.com/CivicStack/civicstack
CivicStack is an open-source repository designed to democratize access to civic technology tools. It offers a curated collection of applications developed by citizens, organizations, and governments from various countries, all aimed at enhancing democratic participation and addressing societal challenges. By classifying these tools by country and providing direct download links, CivicStack enables users to adapt and implement these solutions within their contexts and realities. The platform is a crucial resource for communities seeking to innovate and improve citizen engagement through technology.

Education

2009 - 2013

Engineer's Degree in Software Engineering

National Technological University - Buenos Aires, Argentina

Certifications

MAY 2023 - PRESENT

CSS for JavaScript Developers

Josh W. Comeau

MARCH 2022 - PRESENT

Learning GitHub Actions

LinkedIn

MAY 2021 - MAY 2023

Certified Scrum Master

Scrum Alliance

Skills

Libraries/APIs

React, React Testing Library, React Router, Node.js, Apollo Client, React Final Form, Moment.js, REST APIs, Playwright, Zod, Segment.io

Tools

GitHub, Git, NPM, Jira, Sentry, Google Analytics, Webpack, Apache, Browserify, Stylus, Gulp

Languages

JavaScript, HTML, CSS, TypeScript, GraphQL, ANSI C, Python, Ruby, Groovy, Prolog, Haskell, Smalltalk, PHP

Frameworks

Chrome, Jest, Express.js, Cypress, Yarn, Redux, Material UI, Ruby on Rails (RoR), Tailwind CSS, Electron, Laravel

Paradigms

Requirements Analysis, Scrum, Component-based Development, Search Engine Optimization (SEO), Object-relational Mapping (ORM), Database Design

Industry Expertise

Teaching

Platforms

FinalForms, Heroku, MacOS, Visual Studio Code (VS Code)

Storage

Databases, MongoDB, Datadog, MySQL

Other

Software Development, Software Analysis, System Requirements, Functional Requirements, Technical Requirements, Education, Front-end, Web Development, Full-stack, API Integration, User Requirements, System Design, GraphQL Code Generator, Technical SEO, Web Accessibility, Styled-components, Storybook, Software Design, Leadership, Technical Leadership, Accessibility, Object-oriented Databases, Full-stack Development, MVC Frameworks, Operating Systems, OSI Model, Business Planning, Data Structures, APIs, Design Systems, GitHub Actions, Google Analytics 4, Monorepos, Amplitude, Open Source

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.

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