Shai Mesisterano, Developer in Tel Aviv-Yafo, Israel
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Shai Mesisterano

Verified Expert  in Engineering

JavaScript Developer

Location
Tel Aviv-Yafo, Israel
Toptal Member Since
June 10, 2021

Shai is an expert React developer who's played key roles in delivering large-scale solutions for leading companies. He specializes in a range of full-stack technologies, including React and TypeScript. He delivered a product that served two billion sites and 27 million live engagements per month. Previous roles include Scrum master and team lead. Shai has developed for mobile, tablet, and desktop and executed 50 cross-team features per month from requirements to design, testing, and deployment.

Portfolio

GO7
React, Vanilla JS, Redux-Saga, React Redux, Bootstrap, Storybook, Next.js...
Check Point
JavaScript, React, WebStorm, Gmail, HTML, CSS, NPM, Git, Ext JS, Lua, Redux...
Array, LLC
Svelte, Playwright, Go, RAML, CockroachDB, GitLab, Temporal, Docker, Full-stack...

Experience

Availability

Part-time

Preferred Environment

React, Redux, Redux-Saga, HTML, CSS, JavaScript, Cypress, Yarn, Jest, Material UI

The most amazing...

...product I've built is a real-time system, which was a crucial milestone in the customer's business model. It opened a whole new world of opportunities for them.

Work Experience

Team Lead

2023 - PRESENT
GO7
  • Led a project of 11 front-end developers, successfully delivering a new and innovative front-end infrastructure.
  • Developed a clever way to embed React components seamlessly in simple HTML pages, enhancing the company's ability to build dynamic and interactive user interfaces.
  • Implemented a design system using Storybook, effectively organizing components into distinct categories: atoms, molecules, organisms, templates, and pages, streamlining development and design collaboration.
  • Designed the infrastructure to be agnostic to any back-end system, enabling easy integration with various back-end technologies. The infrastructure also efficiently normalizes requests and responses according to the UI needs.
Technologies: React, Vanilla JS, Redux-Saga, React Redux, Bootstrap, Storybook, Next.js, Webpack, Jest, User Interface (UI), Front-end Development, Front-end, ECMAScript (ES6)

Full-stack Freelance

2021 - PRESENT
Check Point
  • Drove migration of an existing application into a modern application to fulfill new business requirements.
  • Transformed an Ext.js application to React. Existing data structures and views were kept while new components were built using React and its ecosystem, specifically Redux, Saga, and others.
  • Created a hybrid environment allowing the legacy application to live alongside the new one.
Technologies: JavaScript, React, WebStorm, Gmail, HTML, CSS, NPM, Git, Ext JS, Lua, Redux, Redux-Saga, Full-stack, Web Development, System Architecture, Pixel Perfect, APIs, REST APIs, API Design, JSON, REST, API Documentation, Software Analysis, Databases, React Native, JSX, Source Code Review, Code Review, Visual Studio, Sublime Text, IntelliJ IDEA, Single-page Applications (SPA), React Router, HTML DOM, Unit Testing, Full-stack Development, Large-scale Projects, Webpack, React Hooks, Testing, Redux Toolkit, Agile, HTML5, Software Architecture, Interactive UI, API Integration, CI/CD Pipelines, Front-end Architecture, User Interface (UI), Front-end Development, Front-end

Front-end Developer

2022 - 2022
Array, LLC
  • Created a web component with 31 different pages from scratch, using Svelte, based on an internal framework. The component introduced an onboarding process for new customers and a dashboard for existing ones.
  • Wrote 52 Playwright integration tests that ran on CI, filled forms with mock data, and ensured that the expected result returned.
  • Developed a GitLab CI process that generates sample data from a RAML file and replaces the server responses with this data. This technique broke the dependency between the client and the server during tests.
  • Delivered a Temporal workflow that generates a loan report, stores it in a CSV file using Go, and uploads it to Cross River Bank's servers.
Technologies: Svelte, Playwright, Go, RAML, CockroachDB, GitLab, Temporal, Docker, Full-stack, Web Development, System Architecture, Pixel Perfect, APIs, REST APIs, API Design, JSON, REST, API Documentation, Databases, Responsive Web Apps, Source Code Review, Code Review, Visual Studio, Sublime Text, IntelliJ IDEA, Single-page Applications (SPA), HTML DOM, Unit Testing, Full-stack Development, Large-scale Projects, Agile, HTML5, Software Architecture, Sass, Interactive UI, API Integration, CI/CD Pipelines, Front-end Architecture, User Interface (UI), Front-end Development, Front-end, ECMAScript (ES6)

Front-end Freelance

2020 - 2021
Amdocs
  • Created and led the UI development of a new project as the sole front-end developer. This innovative application was used internally by dozens of developers, DevOps engineers, and managers as it introduced real-time information about several SaaS accounts, such as the number of available clusters, pods, and servers.
  • Built the UI dashboard from scratch, using Material-UI, React, TypeScript, Redux, and Redux-saga. The smart UI tables displayed the information in bulk and were able to cache the results in the browser for fast future access; some of the information was transported via WebSockets.
  • Created an E2E automated process (using Cypress.io and Jenkins); it stubbed network requests during runtime, which adds stability and resiliency to the application.
  • Mentored two back-end developers (one is offshore): introduced them to front-end technologies and trained them.
Technologies: React, Redux, Redux-Saga, HTML, CSS, JavaScript, Docker, Jenkins, Trello, OpenShift, Cypress, MacOS, WebStorm, Gmail, Material UI, Bash Script, TypeScript, WebSockets, Socket.IO, Storybook, NPM, React Redux, Front-end Development, Git, Bitbucket, GitLab, Amazon Web Services (AWS), APIs, Application State Management, REST APIs, HTML5, JavaScript 6, API Design, Web Development, System Architecture, Pixel Perfect, JSON, REST, API Documentation, Databases, Web Applications, JSON Web Tokens (JWT), OAuth, JSX, Responsive Web Apps, Serverless, Source Code Review, Code Review, Team Management, Visual Studio, Sublime Text, IntelliJ IDEA, Single-page Applications (SPA), React Router, HTML DOM, Unit Testing, Full-stack Development, Large-scale Projects, Authentication, Recharts, React Hooks, Testing, Redux Toolkit, Agile, Software Architecture, Sass, Interactive UI, API Integration, OAuth 2, Documentation, Technical Documentation, UX Design, CI/CD Pipelines, Front-end Architecture, User Interface (UI), Front-end, ECMAScript (ES6)

Front-end Freelance

2020 - 2020
Check Point
  • Consulted the team leader regarding the application’s infrastructure, team’s technologies, designs, code reviews, and more.
  • Transformed a dashboard screen to be fully responsive using Antd.
  • Refactored critical components, which included separating the business logic from the presentation and improving reusability.
  • Wrote a Bash script that creates a MongoDB database and adds seed data for running E2E tests against it.
Technologies: JavaScript, Node.js, React, React Apollo, Apollo Server, GraphQL, Antd, Cypress, Jest, WebStorm, Gmail, Jenkins, HTML, CSS, Bash Script, MongoDB, Storybook, NPM, Git, Bitbucket, Web Development, Pixel Perfect, APIs, REST APIs, API Design, JSON, REST, API Documentation, Software Analysis, Databases, Web Applications, JSX, Source Code Review, Code Review, Visual Studio, Sublime Text, IntelliJ IDEA, Single-page Applications (SPA), React Router, HTML DOM, Unit Testing, Full-stack Development, Large-scale Projects, React Hooks, Testing, Agile, HTML5, Software Architecture, Sass, Interactive UI, API Integration, CI/CD Pipelines, Front-end Architecture, Tailwind CSS, User Interface (UI), Front-end Development, Front-end

Back-end Node.js Freelance

2019 - 2020
Carlson Wagonlit Travel
  • Built a messaging framework that allows travelers to message agents via different channels (Slack, WhatsApp, Facebook, and more) through webhooks.
  • Integrated Microsoft Teams as a messaging channel between travelers and agents, using my built messaging framework.
  • Created E2E acceptance tests, which send messages from travelers to agents and back and verify that the messages arrived successfully.
Technologies: JavaScript, Node.js, Express.js, Jest, Microsoft Teams, Slack API, Slack, Facebook SDK, Smooch SDK, Webhooks, MacOS, WebStorm, Gmail, Jenkins, HTML, CSS, Docker, Bash Script, MongoDB, Yarn, Web Development, System Architecture, Pixel Perfect, APIs, REST APIs, API Design, JSON, REST, API Documentation, Software Analysis, Databases, Source Code Review, Code Review, Visual Studio, Sublime Text, IntelliJ IDEA, HTML DOM, Unit Testing, Large-scale Projects, Agile, HTML5, Software Architecture, Sass, Interactive UI, API Integration, CI/CD Pipelines, Front-end Architecture, User Interface (UI)

Full-stack Freelance

2018 - 2020
Verint
  • Consulted with the full-stack team lead regarding the application’s infrastructure, team’s technologies, designs, code reviews, etc.
  • Designed and built a UI-component library for React and used Storybook and Yarn to create a convenient way for the team to create and maintain React components in an isolated and extendable environment.
  • Integrated Jest as a unit test library for both the back end (Node.js) and front end (React).
  • Added unit tests and coverage metrics to the CI pipeline to increase the quality and speed of the development cycle.
  • Implemented a real-time notification capability by transferring all incoming messages from RabbitMQ to the Redux store via WebSockets.
  • Created a mono repository using Lerna and Yarn workspaces; it included components, client, and server projects.
Technologies: JavaScript, React, Material UI, Redux-Saga, Redux, Cypress, Bash Script, Node.js, Express.js, TypeScript, Jest, RabbitMQ, WebSockets, Socket.IO, Linux, MacOS, WebStorm, Gmail, Jenkins, HTML, CSS, Docker, Storybook, Yarn, React Redux, Webpack, Full-stack, Web Development, Pixel Perfect, APIs, REST APIs, API Design, JSON, REST, API Documentation, Software Analysis, Databases, Web Applications, JSX, Source Code Review, Code Review, Visual Studio, Sublime Text, IntelliJ IDEA, Single-page Applications (SPA), React Router, HTML DOM, Unit Testing, OpenAPI, Full-stack Development, Large-scale Projects, Testing, Agile, HTML5, Software Architecture, Interactive UI, API Integration, CI/CD Pipelines, Front-end Architecture, User Interface (UI), Front-end Development, Front-end

Front-end Freelance

2019 - 2019
Bond Sports
  • Developed a website that allows scheduling sports activities and leagues.
  • Created a reservation system that contains scheduling an event, adding participants, and buying add-ons.
  • Added a payment option by integrating with Stripe API.
  • Created a layout system for the application, which significantly reduced the amount of code, helping to scale the front-end development and meet the timelines.
Technologies: Next.js, React, TypeScript, Emotion Library, JavaScript, WebStorm, HTML, CSS, Stripe API, Stripe Payments, SCSS, Figma, Balsamiq Mockups, Web Development, Pixel Perfect, APIs, REST APIs, API Design, JSON, REST, API Documentation, Databases, JSX, Responsive Web Apps, Source Code Review, Code Review, Visual Studio, Sublime Text, IntelliJ IDEA, HTML DOM, Unit Testing, Large-scale Projects, Server-side Rendering (SSR), Agile, HTML5, Sass, Interactive UI, API Integration, CI/CD Pipelines, User Interface (UI), Front-end Development, Front-end

Team Lead | Scrum Master | Software Engineer

2014 - 2017
Liveperson
  • Led and empowered six software, QA, and automation engineers.
  • Collaborated with 150 developers, product managers, and architects. Developed and integrated our product in a cloud-based environment that served two billion monitored sites and 27 million live engagements per month across more than 18,000 sites.
  • Executed 50 cross-team features per month from the product requirements stage through the design, execution, review, testing, and automation until the deployment to the company’s seven CDN farms worldwide.
  • Served as the company's focal point concerning the web consumer-facing area and worked closely with project and product managers in the execution of the yearly product roadmap, which involved more than 15 teams.
  • Initiated a QA process that separated the rollout from deployment and helped reach 0% downtime in production.
  • Designed, built, and maintained the consumer-facing chat and messaging solutions, using cutting-edge technologies while executing five new monthly features.
  • Built and maintained the monitoring solution for LivePerson’s reporting and data analysis systems, which helps the company charge customers as part of the freemium business model.
  • Engineered solutions for various problems, including accessibility (level AA), a delivery system deployment tool, cross-domain monitoring, and more.
Technologies: JavaScript, HTML, CSS, Node.js, Mocha, Sinon.JS, Chai, MacOS, WebStorm, Slack, Gmail, Jira, Jenkins, WebSockets, Management, NPM, Git, GitHub, Auth0, Leadership, Team Leadership, Web Development, System Architecture, Pixel Perfect, APIs, REST APIs, API Design, JSON, REST, API Documentation, Databases, JSON Web Tokens (JWT), OAuth, Responsive Web Apps, Technical Hiring, Source Code Review, Code Review, Task Analysis, Interviewing, Team Management, Visual Studio, Sublime Text, IntelliJ IDEA, Single-page Applications (SPA), HTML DOM, Unit Testing, Large-scale Projects, Authentication, Agile, HTML5, WCAG 2, Accessibility, Software Architecture, Sass, Interactive UI, API Integration, OAuth 2, OpenID, CI/CD Pipelines, Front-end Architecture, User Interface (UI), Front-end Development, Front-end

Full-stack Freelance

2014 - 2014
Iron Source
  • Developed a dashboard system with online ad usage statistics using Backbone.js and Backbone.Marionette (front end) and Node.js (back end).
  • Built a proxy tool for QA testers, which simulates ads within external websites and saves the company tens of thousands of dollars per day by preventing production bugs.
  • Constructed an ad-tracking system using Node.js, which gathers information about ads' exposure, clicks, and leads.
  • Developed 200 responsive ads for mobile, tablet, and desktop, which dramatically improved the consumer experience in mobile devices.
Technologies: JavaScript, HTML, CSS, Backbone.js, Backbone.Marionette, Flash, Node.js, MacOS, Gmail, Jira, Jenkins, Full-stack, Web Development, APIs, REST APIs, API Design, JSON, REST, API Documentation, Databases, Responsive Web Apps, Source Code Review, Code Review, Visual Studio, HTML DOM, Unit Testing, Full-stack Development, Large-scale Projects, Agile, HTML5, Sass, Interactive UI, API Integration, User Interface (UI), Front-end Development, Front-end

Full-stack Freelance

2011 - 2014
ooVoo
  • Maintained the company's official website. The website was built using HTML, CSS, JavaScript, jQuery, and ASP.NET and was hosted in IIS servers.
  • Created landing pages with forms for special campaigns, like the Christmas one.
  • Developed a platform for testing the REST API on the mobile, web, PC, and macOS environments. The platform allowed ten testers to test the product in multiple environments at the same time.
Technologies: HTML, CSS, JavaScript, ASP.NET, jQuery, MacOS, Gmail, Full-stack, Web Development, APIs, REST APIs, API Design, JSON, REST, API Documentation, Databases, Source Code Review, Code Review, C#, Visual Studio, .NET, HTML DOM, AngularJS, Full-stack Development, Large-scale Projects, Server-side Rendering (SSR), SQL, HTML5, Sass, Interactive UI, API Integration, Documentation, Technical Documentation, User Interface (UI), Front-end Development, Front-end

Full-stack Freelance

2009 - 2011
LoveMe
  • Created a chat application for Israel’s leading dating website. The chat was based on Ajax, which was cutting-edge technology back then.
  • Cut and coded about 300 landing pages for online-interactive campaigns using Flash.
  • Created about 100 interactive-Flash ads, which were published on Israel's most popular websites: Ynet, Walla, Panet, and more.
Technologies: HTML, CSS, JavaScript, MooTools, ASP.NET, Flash, Photoshop 7, Gmail, Full-stack, Web Development, API Documentation, Databases, Source Code Review, Code Review, C#, Visual Studio, .NET, HTML DOM, Full-stack Development, Server-side Rendering (SSR), SQL, Interactive UI, User Interface (UI), Front-end Development, Front-end

Owner

2006 - 2009
MCterano.com
  • Established a private business and handled all its aspects, including management, sales, marketing, publishing, PR, and engineering.
  • Created a custom CMS from scratch, based on ASP.NET. The customers used the system for full website management (content pages, contact forms, image galleries, and more).
  • Recruited two employees (a graphic designer and a full-stack developer).
Technologies: HTML, JavaScript, CSS, ASP.NET, Gmail, Flash, Management, Photoshop 7, MySQL, WordPress, Full-stack, Web Development, Databases, GitHub, Source Code Review, Code Review, C#, Visual Studio, .NET, HTML DOM, Server-side Rendering (SSR), SQL, Interactive UI, UX Design, User Interface (UI), Front-end Development, Front-end

A Credit Builder For Array.com (One of Forbes' "Next Billion-Dollar Startups 2021")

https://www.buildcredit.com
The Credit Builder helps people establish credit scores and build credit history.

I received Figma designs as a reference for about 30 web pages. My mission was to turn the designs into a live web component using Svelte. I developed the web component from scratch for both mobile and desktop. Some of the designs were related to the registration process, and the others to a dashboard.

I managed to build the component E2E within three months and received great feedback from the client. I also built an automation tool that covered the process with more than 50 tests. The tool was adopted by the rest of the company after it increased the product's quality significantly.

TESTIMONIAL

"Highly skilled, organized, professional, friendly, communicative, and helpful only begins to describe Shai. He is a top-tier dev and a great person. I can't recommend him enough!" – Joe Schwehr, Software Engineer

An Omnichannel Solution for Carlson Wagonlit Travel (CWT)

https://appsource.microsoft.com/en-us/product/office/wa200001675?tab=overview
Created an omnichannel solution that allowed CWT's customers to perform actions such as booking a flight and ordering a hotel room. Customers could engage with CWT with a mobile phone via their website, move to another channel like Facebook Messenger or Slack, and continue the conversation from where they left it.

On the technical aspect, I created a microservices architecture to deliver the solution. A messaging service was created to listen to user operations via Webhooks. From there, an abstract layer written in Express.js communicated with a vendor service, e.g., Slack, Facebook, Teams, etc., via a RESTful API. I created a service for each vendor and integrated our solution with its API. The new data was stored in a MongoDB database. Once the database was updated, the other channels were notified through the messaging service. All services ran on Docker instances.

The chosen architecture allowed the solution to scale. New vendors like Twilio, Gmail, and others could be added easily, and the company gained a huge advantage over its competitors by being able to build new features with minimal effort and customize them according to the customers' needs.

A Messaging Platform for LivePerson

http://www.liveperson.com
Created a WebSockets-based messaging solution for LivePerson. I took the legacy product, which included an option to chat with agents only in real time, and transformed it into a modern application that allows consumers to leave a message to an agent, have asynchronous conversations (WhatsApp style), take a survey, and more.

TESTIMONIALS

"Shai is one of the most diligent, detail-oriented and clear [sic] I've worked with. We've gone through complicated times prioritizing and hacking bugs and tasks for high-paying customers. In these times, having a person who can provide honest timelines and deliver upon them is *priceless*." – Maor Bluman, Product Manager

"I had the opportunity to work with Shai at Liveperson. Shai owns a unique skill that is a key to success for any engineering team: he is capable of finding a way to each and every person, understanding him/her, no matter how different or opposite they are. This skill and the power of doubting assumptions in order to reach the best quality of features delivery make him an asset." – Adiel Ivantsiv, Software Engineer
2013 - 2016

Bachelor's Degree in Business Administration

The Open University - Ra'anana, Israel

MARCH 2009 - PRESENT

Marketing Management

Tel Aviv University

Libraries/APIs

React, Redux-Saga, Node.js, Antd, REST APIs, React Router, OpenID, Socket.IO, Sinon.JS, Chai, Playwright, OpenAPI, Recharts, Slack API, Facebook SDK, Backbone.js, Backbone.Marionette, jQuery, MooTools, React Redux, Emotion Library, Stripe API, Facebook API

Tools

Flash, NPM, GitHub, JSX, Sublime Text, IntelliJ IDEA, Redux Toolkit, Babel, WebStorm, Trello, Mocha, Webpack, Visual Studio, Slack, Jira, Jenkins, React Apollo, Microsoft Teams, Smooch SDK, RabbitMQ, Photoshop 7, Git, Bitbucket, GitLab, Auth0, Figma, Balsamiq Mockups

Frameworks

Redux, Material UI, Yarn, Next.js, Svelte, JSON Web Tokens (JWT), OAuth 2, Tailwind CSS, Cypress, Jest, Express.js, React Native, AngularJS, ASP.NET, Ext JS, Vanilla JS, .NET, Bootstrap

Languages

HTML, CSS, JavaScript, Bash Script, TypeScript, HTML5, Sass, CSS3, SQL, ECMAScript (ES6), GraphQL, SCSS, JavaScript 6, Lua, Go, C#

Paradigms

Management, REST, HTML DOM, Unit Testing, Agile, Testing, Responsive Web Design (RWD), UX Design, Business Intelligence (BI)

Storage

JSON, MongoDB, Databases, MySQL, CockroachDB, PostgreSQL

Industry Expertise

Project Management

Platforms

Linux, MacOS, Docker, OpenShift, Amazon Web Services (AWS), WordPress

Other

Storybook, Front-end Development, Full-stack, Web Development, System Architecture, Client-side, Front-end, Architecture, Styled-components, Pixel Perfect, API Documentation, Software Analysis, Web Applications, Full-stack Development, OAuth, Responsive Web Apps, Source Code Review, Code Review, Single-page Applications (SPA), Large-scale Projects, Server-side Rendering (SSR), React Hooks, Software Architecture, Interactive UI, API Integration, Documentation, Technical Documentation, Front-end Architecture, Cross-browser Compatibility, Responsive Design, Technical Leadership, Web Usability, User Interface (UI), Material Design, UI Components, Design Systems, WebSockets, APIs, API Design, Back-end, Technical Hiring, Task Analysis, Interviewing, Team Management, Authentication, WCAG 2, Accessibility, CI/CD Pipelines, Gmail, Apollo Server, Webhooks, Public Relations (PR), Stripe Payments, Application State Management, Leadership, Team Leadership, RAML, Temporal, Serverless

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