Ronen is available for hire

Ronen Elster

Verified Expert in Engineering

Front-end Developer

Location

Tel Aviv-Yafo, Israel

Toptal Member Since

April 29, 2021

Ronen is a front-end developer with a decade of experience. He has developed cross-browser support for unsupported browsers up to IE9 enabled for JavaScript and CSS, led massive refactor projects of legacy web applications that used outdated technologies, and created pixel-perfect websites based on PSD designs. He focuses on optimization and looks for where code might break down. Ronen has published native mobile apps to the Google Play Store and Apple App Store and enjoys mentoring developers.

Portfolio

Freelance Clients

React, Full-stack, Next.js, Redux, JavaScript, ECMAScript (ES6)...

Pibble LLC

CSS, JavaScript, HTML, API Integration, Google Analytics, User Interface (UI)...

Augury

JavaScript, CSS, HTML, AngularJS, React, Puppeteer, Git, GitHub, Redux...

Experience

JavaScript - 13 years RTL - 11 years Async.js - 7 years Git - 6 years GitHub - 6 years React - 6 years REST - 5 years TypeScript - 4 years

Availability

Part-time

Preferred Environment

MacOS, Vue, React, JavaScript, CSS, HTML, Browsers, Node.js, Express.js, MongoDB, Continuous Integration (CI), Test-driven Development (TDD), Web & Mobile Applications, Puppeteer, Sentry, Open Broadcaster Studio (OBS)

The most amazing...

...product I've developed is a file uploader that allows uploading multiple (very large) files over long periods, with retry functionality and error handling.

Work Experience

Senior Vue & Full-stack React Developer

2023 - 2023

Freelance Clients

Developed a web-based application based on Nuxt 3 and Vue 3 as a senior Vue developer for a Web3 project.
Built a React/Next.js application for email-based content as a senior full-stack React developer for a marketing and advertising company.
Helped solve deployment-related issues in the React/Next.js application.

Technologies: React, Full-stack, Next.js, Redux, JavaScript, ECMAScript (ES6), CI/CD Pipelines, Python, PHP, WordPress, Create React App, Mobile First, Vue, Web3, Full-stack Development, Front-end, Front-end Development, Crypto, Proof of Concept (POC), ChatGPT, Vercel, Accessibility, Monorepos, Data Architecture, Marketing

Front-end Developer

2023 - 2023

Pibble LLC

Developed a responsive landing page with CSS, HTML, and JavaScript.
Worked with HTML templates using the PHP programming language.
Collaborated with a designer and full-stack developer on the back end.

Technologies: CSS, JavaScript, HTML, API Integration, Google Analytics, User Interface (UI), User Experience (UX), Front-end, PHP, Bootstrap, WordPress, Search Engine Optimization (SEO), Responsive Web Design (RWD), SEO Tools, Mobile First

Senior Front-end Developer

2022 - 2023

Augury

Developed a web app dashboard for users interacting with the company services.
Tracked and fixed bugs using tools such as Dapulse and others.
Assisted junior team members and mentored them with learning React.
Performed code reviews on GitHub pull requests and added detailed pull requests of my own.

Technologies: JavaScript, CSS, HTML, AngularJS, React, Puppeteer, Git, GitHub, Redux, React Redux, Dapulse, Wrike, Azure, TypeScript, Node.js, Jest, Jenkins, Jenkins Pipeline, Cypress, E2E Testing, Dashboards, Data Visualization, Graphs, Figma, Web Development, Animation, Architecture, Chart.js, Mentorship, Software Troubleshooting, Agile, Estimations, CI/CD Pipelines, Styled-components, Microservices, Google Cloud, Automated Testing, Google Cloud Platform (GCP), Third-party Integration, JSON, Front-end Architecture, Best Practices, Boilerplate Code, Docker Compose, Continuous Delivery (CD), Front-end Design, Web App UX, Software Architecture, Project Consultancy, UI Design, Webhooks, Automation, HTML5, UI Development, Charts, Cross-browser Compatibility, Create React App, Mobile First, XML, HTML5 Animations, Transitions

React Front-end Developer

2021 - 2022

A51 LTD

Developed a web app that allows bookmarking of all kinds of data from the web.
Mentored and assisted the junior team members with regard to the front-end. I also conducted interviews.
Explored developing a browser extension for Chrome for the web app.

Technologies: React, TypeScript, JavaScript, Node.js, MobX, Chrome, Extensions, Git, Azure, GitHub, Jest, Cypress, Chromium, Azure Blobs, REST APIs, REST, Data Visualization, Figma, Web Development, Animation, Architecture, Blockchain, Early-stage Startups, Search Engine Optimization (SEO), Responsive Web Design (RWD), Software Troubleshooting, Agile, Estimations, CI/CD Pipelines, Styled-components, OAuth, Single Sign-on (SSO), Stripe, Third-party Integration, JSON, Front-end Architecture, Best Practices, Boilerplate Code, Docker Compose, Continuous Delivery (CD), Auth0, Front-end Design, Web App UX, Software Architecture, Project Consultancy, Plugins, Minimum Viable Product (MVP), Startups, Iframes, Automation, HTML5, UI Development, MERN Stack, Chrome Extensions, Web App Design, Web Security, Cross-browser Compatibility, Create React App, Proof of Concept (POC), XML, HTML5 Animations, Transitions

Front-end Developer

2021 - 2022

Array, LLC

Developed widgets using JavaScript Web Components API for a financial services project. Utilized Vanilla JavaScript for the project.
Developed widgets for the company using the Svelte library.
Communicated with team members across the world in a distributed team.

Technologies: JavaScript, Front-end, Vanilla JS, Svelte, Web Components, Graphs, Figma, Web Development, Search Engine Optimization (SEO), Software Troubleshooting, Agile, Estimations, Widgets, JSON, Payment APIs, Front-end Architecture, Best Practices, Boilerplate Code, Docker Compose, Continuous Delivery (CD), Auth0, Front-end Design, Web App UX, Project Consultancy, Iframes, HTML5, UI Development, Charts, Web Security, Cross-browser Compatibility, Mobile First, HTML5 Animations, Transitions

Senior Front-end Developer

2021 - 2022

Freelance

Participated in developing the back office and user-facing client-side using server-side rendering (SSR) and single-page application (SPA) via Next.js and React. I was part of a team of developers on this project.
Tracked and fixed bugs using Jira and Kanban as a reporting tools.
Increased the total performance and speed of the user-facing site.

Technologies: JavaScript, React, Next.js, ESLint, CSS, Webpack, Storybook, Unit Testing, Async.js, REST, Git, GitHub, Jira, Kanban, Slack, TypeScript, Application State Management, Recoil, JSX, Performance, APIs, Google Analytics, RxJS, Code Review, Source Code Review, Task Analysis, Material UI, Emotion Library, ES6 Promises, Async/Await, Continuous Integration (CI), Front-end Development, Full-stack Development, Ant Design, Tailwind CSS, Cypress, Testing, User Experience (UX), User Interface (UI), Web UI, Web UX, API Integration, Web Applications, Content Management Systems (CMS), Babel, Dashboards, Data Visualization, Graphs, Booking Systems, Figma, Web Development, Technical Leadership, Architecture, Server-side Rendering (SSR), Early-stage Startups, Search Engine Optimization (SEO), Responsive Web Design (RWD), Software Troubleshooting, iOS, Android, Google Play Store, App Store, Estimations, CI/CD Pipelines, Styled-components, Google Cloud, OAuth, Third-party Integration, JSON, Payment APIs, Front-end Architecture, Best Practices, Boilerplate Code, Continuous Delivery (CD), Front-end Design, Project Consultancy, Plugins, Ionic, Email Templates, HTML5, UI Development, MERN Stack, Web Security, Cross-browser Compatibility, Create React App, Mobile First, Proof of Concept (POC), XML, HTML5 Animations, Transitions

Senior Front-end Developer

2019 - 2022

Freelance

Participated in developing the back office and user-facing client side using server-side rendering (SSR) and single-page application (SPA) via Nuxt.js and Vue.
Published the site as a native mobile app on the Google Play Store and Apple App store, first using Ionic and later with another solution.
Guided the solutions for hard-to-debug performance issues such as memory leaks.
Served as an external consultant and point-of-contact for technical front-end issues. Assisted in the mentoring and advising of junior developers.
Assisted in the implementation of several analytics solutions for the company. Due to technical restrictions, the solution required interacting with the server in unusual ways. e.g, some of the work the server would do was done on the client side.

Technologies: Nuxt.js, Vuex, Vue, Vue CLI, Vue SSR, Vue 2, Express.js, IIS, Analytics, Web Analytics, Code Review, Source Code Review, Refactoring, Task Analysis, Continuous Integration (CI), Test-driven Development (TDD), Web & Mobile Applications, Puppeteer, Data Analysis, Cross-platform App Development, Mobile App Development, Front-end Development, Full-stack Development, NestJS, Tailwind CSS, Cypress, Testing, User Experience (UX), User Interface (UI), Web UI, Web UX, API Integration, Web Applications, Babel, Storybook, TypeScript, Dashboards, Data Visualization, Graphs, Web Development, Video Streaming, Email, Responsive Web Design (RWD), Mentorship, Software Troubleshooting, Estimations, Vuetify, JSON, Best Practices, Boilerplate Code, Continuous Delivery (CD), Project Consultancy, HTML5, UI Development, MERN Stack, Cross-browser Compatibility, Create React App, Mobile First, XML, Markdown

Senior Front-end Developer

2018 - 2020

Freelance

Assisted in the development of the user-facing dashboard of the company service back office.
Developed the front-end for a complex permissions and policy rules feature.
Created a solution for uploading massive video files in chunks to a cloud platform provider. Developed a feature to retry uploads in case of failure. In the process I increased performance of an existing, older solution.
Guided the transition of the front end from Angular to another solution. Created a POC with Vue.js first and later with React.
Served as an external consultant, mentored junior developers, and solved hard-to-debug issues on the client side.
Participated in meetings with all stakeholders on the development process for the company, an established corporation.

Technologies: Angular, Redux, Redux-observable, RxJS, React, JSX, Performance, Website Performance, Site Speed Optimization, Code Review, Source Code Review, Interviewing, Technical Hiring, Google, Continuous Integration (CI), Front-end Development, Full-stack Development, Amazon DynamoDB, AWS Lambda, Tailwind CSS, Testing, User Experience (UX), User Interface (UI), Web UI, Web UX, API Integration, Web Applications, Babel, Storybook, Electron, Web Development, React Native, Responsive Web Design (RWD), Mentorship, Software Troubleshooting, New Relic, CI/CD Pipelines, Best Practices, Boilerplate Code, Continuous Delivery (CD), Responsive Email Templates, MERN Stack, Cross-browser Compatibility

Senior Front-end Developer

2017 - 2019

Freelance

Led a massive refactor of a legacy web application single handedly that was using outdated technologies. Eliminated thousands of lines of code, installed web tools, modern tools, automation, and documentation on both the front end and back end.
Implemented a functionality that masked bad network connectivity and made the browsing experience seamless for the user.
Implemented a WebView solution for the main product. Integrated an existing web application into a WebView wrapper according to the customer's. specifications.
Implemented Google Analytics with real-time results.

Technologies: JavaScript, ES6 Promises, MongoDB, Express.js, Node.js, PHP, React, Redux, Vue, Vuex, Vue CLI, JSX, Website Performance, Performance, Site Speed Optimization, Optimization, Refactoring, Code Review, Google Analytics, Google Analytics API, Source Code Review, Google, Front-end Development, Testing, User Experience (UX), User Interface (UI), Web UI, Web UX, Web Applications, Cryptography, Babel, Advertising Technology (Adtech), Matomo, Amazon Web Services (AWS), Web Development, Search Engine Optimization (SEO), Responsive Web Design (RWD), Software Troubleshooting, iOS, Android, Google Play Store, App Store, Estimations, CI/CD Pipelines, YouTube API, Third-party Integration, JSON, Best Practices, Boilerplate Code, Continuous Delivery (CD), C++, Google Ads, Quasar, Email Templates, Responsive Email Templates, MERN Stack, Cross-browser Compatibility

Senior Front-end Developer

2015 - 2016

Spot.IM

Assisted in the development of a user profile feature for the users.
Enabled cross browser support for previously unsupported older browsers, up to IE9 level. Support was enabled for both JavaScript and CSS.
Solved a large number of bugs and issues using several task dashboards over time.

Technologies: React, Brower, BrowserStack, Code Review, Source Code Review, Task Analysis, Front-end Development, User Experience (UX), User Interface (UI), Web UI, Web UX, Web Applications, Babel, Web Development, Early-stage Startups, Search Engine Optimization (SEO), Responsive Web Design (RWD), Estimations, Databases, Widgets, Third-party Integration, JSON, Model View Controller (MVC), Best Practices, Boilerplate Code, Continuous Delivery (CD), Iframes, Cross-browser Compatibility, Windows, Pixel Perfect

Full-stack Developer

2013 - 2015

TradeSmarter

Developed a permissions grant and policy rules feature on both the front end and back end.
Created pixel-perfect websites based on PSD designs.
Built WordPress sites and added custom features per customer specifications.

Technologies: JavaScript, CSS, Less, PHP 5, PHP MVC, MySQL, WordPress, UI Animation, Front-end Development, User Experience (UX), User Interface (UI), Web UI, Web UX, Full-stack, Java, Web Applications, Web Development, Search Engine Optimization (SEO), Estimations, Databases, Back-end, Third-party Integration, JSON, Model View Controller (MVC), Best Practices, Cross-browser Compatibility, Windows, Pixel Perfect

Full-stack Developer

2011 - 2012

STG Digital

Turned static photoshop designs into pixel-perfect web pages.
Customized customer requests with proprietary modular CMS written with PHP.
Developed cross-browser support even for extremely old browsers-all the way back to IE6.

Technologies: jQuery, jQuery UI, Web Animation, CSS, UI Animation, Front-end Development, Full-stack Development, User Experience (UX), User Interface (UI), Web UI, Web UX, Full-stack, Web Applications, Web Development, C#, .NET, Search Engine Optimization (SEO), .NET Core, Visual Studio, Databases, Back-end, Algorithms, JSON, Best Practices, Cross-browser Compatibility, Windows, Pixel Perfect

Experience

Tutorial Site for ECMAScript 6 in Hebrew

https://ronen-e.github.io/understandinges6/

A docsify-based website for presenting translated content of the book Understanding ES6 by Nicholas C. Zakas.

I assisted in writing and editing the original content. I later acquired the translation rights from the publisher and set out to add the content in Hebrew - a right-to-left language. I encountered many issues with the RTL requirements and overcame them. I published the content on a website that can parse Github markdown. I tried Gitbook and when that didn't work well I found docsify to be a better alternative.

While translating, I also encountered content challenges and was in communication with the author to help clarify. I added issues in the main Github repository. The developer community also assisted me in this project.

The majority of the work was done by myself. A few chapters were initially translated by other contributors. Their names appear in the project repository. I thank them for their help. I am currently in the final stages of proofing the content.

File Upload and Processing

A JavaScript-based tool to facilitate uploading multiple extremely large files,
hundreds, or even thousands, to a cloud environment or to an internal server.
I was the front-end developer and liaised with the back-end developer to implement the procedure flowing correctly. The files were first uploaded and then processed on the server. The process included real-time notification for the status of each file as well as backup and retry functionality to avoid time loss.
During the process, I found ways to optimize the existing upload speed by at least 30%.

Server Side Rendered Single Page Application with Nuxt.js

A complete revamp of an older design, built from scratch on the front-end side. I was hired as a senior developer to mentor and assist a team of developers. The framework used was Nuxt.js to help with the server-side rendering (SSR) to avoid any loss of SEO benefits from the old site. All the old site links were redirected to the new website. On top of that, I wrapped the website with a mobile native solution to use on Apple and Google's app stores. The website was optimized to run with high performance. Along the way, I encountered many issues, technical and others, which, together with the team, I solved to the customer's full satisfaction.

Understanding JavaScript Promises in Hebrew

https://leanpub.com/understanding-javascript-promises-he/

A collaborative effort with author Nicholas C. Zakas to translate the book Understanding JavaScript Promises.

This was the first translation done in an RTL language, and we encountered several issues during the process, which we eventually overcame.

Skillset

Languages

JavaScript, CSS, HTML, TypeScript, ECMAScript (ES6), Regex, HTML5, GraphQL, PHP, Sass, SCSS, XML, PHP 5, Python, Ruby, CSS3, CoffeeScript, SQL, Less, Java, C#, C++, Markdown

Frameworks

Next.js, Redux, Material UI, Nuxt.js, Vue SSR, Jest, Angular, AngularJS, Bootstrap, Tailwind CSS, Cypress, Vuetify, Quasar, Express.js, Flux, Realtime, Protractor, Django, Ruby on Rails (RoR), Ember.js, PHP MVC, Laravel, Relay, Ant Design, NestJS, Vanilla JS, Svelte, Chrome, Electron, React Native, .NET, .NET Core, Ionic

Libraries/APIs

Vue, React, Node.js, Vue 2, React Redux, jQuery, REST APIs, Flexbox, Vuex, jQuery UI, MobX, Puppeteer, RxJS, WebRTC, Cache API, Immutable.js, Ember Data, Backbone.js, Google Analytics API, Emotion Library, MobX-State-Tree (MST), Jenkins Pipeline, Chart.js, YouTube API, Stripe

Tools

F12 Developer Tools, Babel, Git, GitHub, Webpack, Slack, Chrome Developer Tools, MF Upload, JSX, Mocha, UI Grid, Google Analytics, Figma, Create React App, Jira, Firebase Authentication, Canvas, Gulp, Grunt, Vue CLI, Shell, BrowserStack, Sentry, Matomo, Wrike, Jenkins, Visual Studio, Docker Compose, Auth0, Open Broadcaster Studio (OBS), ChatGPT

Paradigms

REST, Refactoring, Best Practices, Unit Testing, Functional Programming, Automation, Testing, Search Engine Optimization (SEO), Responsive Web Design (RWD), Agile, Model View Controller (MVC), Continuous Delivery (CD), Web App Design, Kanban, Design Patterns, Reactive Programming, Asynchronous Programming, Dependency Injection, DevOps, E2E Testing, Continuous Integration (CI), Test-driven Development (TDD), Microservices, Automated Testing, UI Design

Storage

JSON, Web Forms, MongoDB, Cache, MySQL, Amazon DynamoDB, Azure Blobs, Databases, Google Cloud

Other

Browsers, RTL, Right-to-Left (RTL) Scripts, Async.js, Application State Management, ES6 Promises, Front-end, Regular Expressions, Brower, Websites, Web Application Forms, Code Review, APIs, Source Code Review, Front-end Development, User Experience (UX), User Interface (UI), Web UI, Web UX, Web Applications, Dashboards, Web Development, Software Troubleshooting, Estimations, Styled-components, Third-party Integration, Iframes, UI Development, Cross-browser Compatibility, Pixel Perfect, Responsive UI, Docsify, Communication, Storybook, UI Components, HTTP, WebSockets, Storage, Responsive Design, Vue Router, Optimization, Rendering, Website Performance, Performance, HTML Email, CSS3 Animation, Web Animation, Internationalization, Website Optimization, Content Management Systems (CMS), Site Speed Optimization, UI Animation, Cross-platform App Development, Full-stack Development, API Integration, Full-stack, Data Visualization, Graphs, Booking Systems, Animation, Technical Leadership, Video Streaming, Architecture, Email, Server-side Rendering (SSR), Early-stage Startups, Mentorship, Back-end, Widgets, Payment APIs, Front-end Architecture, Boilerplate Code, Front-end Design, Web App UX, Project Consultancy, Plugins, Minimum Viable Product (MVP), Startups, Email Templates, Responsive Email Templates, MERN Stack, Charts, Web Security, Mobile First, Proof of Concept (POC), Monorepos, Data Architecture, HTML5 Animations, Transitions, Web Content, Open Source, ESLint, Recoil, Forms, Redux-observable, Web Accessibility, HTTP 2, HTTPS, SSL, Servers, Fetch API, Service Workers, SVG, SVG Animation, Programming, Ember CLI, Command-line Interface (CLI), Shell Commands, Website Setup, IIS, Analytics, Web Analytics, Interviewing, Technical Hiring, Task Analysis, Async/Await, Google, Web & Mobile Applications, Data Analysis, Mobile App Development, Cryptography, Advertising Technology (Adtech), Web Components, Extensions, Dapulse, Chromium, Design, Google Play Store, App Store, CI/CD Pipelines, OAuth, Single Sign-on (SSO), Algorithms, Software Architecture, Webhooks, Google Ads, Chrome Extensions, Crypto, Web3, SEO Tools, Accessibility

Platforms

MacOS, WordPress, iOS, Android, Windows, Firebase, Docker, Mobile, Web, AWS Lambda, Azure, Amazon Web Services (AWS), Blockchain, New Relic, Google Cloud Platform (GCP), Vercel

Industry Expertise

Marketing, Web Design

Certifications

JULY 2021 - PRESENT

GraphQL: Data Fetching With Relay

JULY 2021 - PRESENT

GraphQL Essential Training

JUNE 2021 - PRESENT

Manage Complex State in React Apps with MobX

egghead.io

JUNE 2021 - PRESENT

Manage Application State with Mobx-state-tree

egghead.io

JUNE 2021 - PRESENT

Migrating from REST to GraphQL

JUNE 2021 - PRESENT

Building a GraphQL Project with React.js

MARCH 2021 - PRESENT

OCTOBER 2016 - PRESENT

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