Sergey Eremeev, Developer in Moscow, Russia
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Sergey Eremeev

Verified Expert  in Engineering

Ethers.js Developer

Moscow, Russia
Toptal Member Since
June 7, 2019

Sergey has nearly a decade of experience in web development working with teams on projects that have shaped the industry—such as large-scale eCommerce platforms serving as outlets for giants like Walmart and small-scale web apps which helped secure contracts with companies like Calvin Klein. Sergey is not the type of developer to rest on his laurels, so he’s continuously perfecting his skills via learning, experimentation, and blogging.


Ziv Livnat
JavaScript, Python, Mapbox, Angular, QGIS, Web Development, API Integration...
Socol Pte Ltd
React Native, React, TypeScript, JavaScript, Next.js, Node.js, Prisma...
JavaScript, React, Python, GraphQL, Less, Jira, Agile, TypeScript, Back-end...




Preferred Environment

GraphQL, Test-driven Development (TDD), Django, Python, Node.js, Vue, React, REST, JavaScript, Git, Back-end, Web Development, MongoDB, MERN Stack, Technical Leadership, Express.js, APIs, REST APIs, API Integration, TypeScript, Full-stack, CTO, GitHub, Architecture, Server-side Rendering (SSR), Application Architecture, Serverless, PostgreSQL, Functional Programming, SQL, HTML5, Object-oriented Programming (OOP), Unit Testing, Laminas, Stripe API, Stripe Payments, Stripe Checkout, Amazon Web Services (AWS), Amazon EC2, Payment APIs, Binance API, Electron, Laravel

The most amazing...

...project I've worked on is a React app that processes complex map data to display relationships between UK region demographics and higher education attendance.

Work Experience

Mapbox Vector Tiles Expert

2022 - 2022
Ziv Livnat
  • Developed a highly complex geocoding system for managing real estate properties on various scales.
  • Used the most up-to-date version of AngularJS to create a highly dynamic front-end application making the filtering and marking of different areas as user-friendly as possible.
  • Achieved a very high performance for large data containing hundreds of thousands of map tiles representing even the smallest areas.
  • Reached a very high level of customization for the app allowing the user to create their own tiles and presets on the fly, load saved data at a later point in time, and apply various visual filters to the points of interest.
Technologies: JavaScript, Python, Mapbox, Angular, QGIS, Web Development, API Integration, TypeScript, Full-stack, GitHub, Application Architecture, JSON, Functional Programming, HTML5, Object-oriented Programming (OOP)

Head of Development | NFT Social Platform

2021 - 2022
Socol Pte Ltd
  • Led the team of developers to create a union of high complexity between social networks, eCommerce, and blockchain, resulting in a high-performing platform, allowing users to connect and achieve things that cannot be done on regular social networks.
  • Participated in assessing the work of developers, measuring their performance, and shaping the team to reach the best results in the shortest periods, saving funds for the client.
  • Took an essential part in designing the overall architecture, consisting of numerous APIs and SDKs for web and mobile (cross-platform) platforms.
  • Suggested and implemented key features, including databases, microservices, payment methods, performant back-end functions, and efficient payment algorithms.
  • Participated in daily stand-ups with developers, weekly reports to higher management, and occasional syncs with the marketing team to ensure the entire company was aware of the progress and the marketing team could perform as efficiently as possible.
Technologies: React Native, React, TypeScript, JavaScript, Next.js, Node.js, Prisma, Blockchain, Web3.js, Infura, MySQL, Amazon S3 (AWS S3), Figma, Ethers.js, PlanetScale, Tailwind CSS, NPM, Contentful, Back-end, AWS Lambda, Lambda Functions, Twilio, VoIP, Web Development, MongoDB, MERN Stack, Technical Leadership, Express.js, APIs, REST APIs, API Integration, Full-stack, CTO, Smart Contracts, GitHub, Architecture, Server-side Rendering (SSR), Application Architecture, Serverless, Software Architecture, iOS, Android, PostgreSQL, OAuth 2, JSON, SQLAlchemy, Terraform, DevOps, SQL, HTML5, Object-oriented Programming (OOP), Unit Testing, Stripe API, Stripe Payments, Stripe Checkout, Amazon Web Services (AWS), Amazon EC2, Payment APIs, Dashboards, Admin Panels

Senior Full-stack Developer

2020 - 2021
  • Maintained the site and added various improvements to the industry-leading social network serving millions of users worldwide.
  • Developed and participated in the design phase of a feature visible to millions of users, which aimed to improve the safety of the end-users.
  • Took part in shaping the architecture of the new features developed over the 2020-2021 period for the consumer safety team.
Technologies: JavaScript, React, Python, GraphQL, Less, Jira, Agile, TypeScript, Back-end, Web Development, MongoDB, MERN Stack, APIs, REST APIs, API Integration, Full-stack, GitHub, Architecture, Application Architecture, Software Architecture, PostgreSQL, OAuth 2, JSON, SQLAlchemy, Functional Programming, Terraform, DevOps, SQL, HTML5, Object-oriented Programming (OOP), Unit Testing, Amazon Web Services (AWS), Amazon EC2, Dashboards, Admin Panels

Full-stack Developer

2019 - 2019
  • Cleaned up a large portion of legacy code and rewritten the cart and checkout pages completely to utilize React and Redux.
  • Incorporated test-driven development into the development process.
  • Further expanded the testing side of the project to utilize both unit testing (Jest) and end-to-end testing (Cypress).
  • Participated in both front and back-end parts of the development process to shape the way the data comes from the back-end to ensure the best integration between all application parts.
  • Heavily participated in brainstorming and provided lots of useful ideas for the application to be more appealing to the end user.
Technologies: Git, HTML, Test-driven Development (TDD), Node.js, REST, CSS, Flask, Django, Python, Cypress, Jest, Redux, React, JavaScript, Back-end, Web Development, MERN Stack, Full-stack, GitHub, JSON, HTML5, Object-oriented Programming (OOP), Unit Testing, Payment APIs, Dashboards

Full-stack Developer

2018 - 2019
  • Developed a process of optimizing 1GB+ files of complex map data to be displayed efficiently in the React web application.
  • Optimized multiple WordPress websites—scoring 95+ on Google PageSpeed.
  • Developed a custom translation mechanism for a Vue.js application—enabling the support of many languages.
  • Took part in developing a WordPress PHP framework for the simpler creation of custom website blocks.
  • Developed a plugin that scans a website for cookie usage and generates an easy-to-use cookie table and a front-end interface for a cookie bar and popup to make a website GDPR compliant.
Technologies: Git, jQuery, HTML, Node.js, REST, CSS, SCSS, WordPress, Webpack, Vue, React, PHP, JavaScript, Back-end, Ruby on Rails (RoR), Web Development, Squarespace, MongoDB, MERN Stack, Technical Leadership, Express.js, APIs, REST APIs, API Integration, Shopify API, Full-stack, GitHub, Architecture, Server-side Rendering (SSR), Application Architecture, Firebase, OAuth 2, JSON, DevOps, SQL, HTML5, Object-oriented Programming (OOP), Unit Testing, Zend Framework, Payment APIs, Dashboards, Admin Panels, Chart.js, Auth0, Laravel

Front-end Developer

2014 - 2018
  • Took part in developing a large-scale eCommerce solution which helped secure a contract with Walmart.
  • Developed a complex custom checkout solution with PHP and vanilla JavaScript.
  • Created a React application for an industry-changing car leasing platform.
  • Participated in the creation of a leading auto auction house application built with Meteor.
  • Developed a highly visual-rich application for a digital marketing agency built with vanilla JavaScript that utilizes custom-created JavaScript and CSS animations.
Technologies: Git, jQuery, HTML, CSS, Magento, WooCommerce, WordPress, React, Meteor, Gulp, Grunt, SCSS, JavaScript, Shopify, Web Development, Technical Leadership, Express.js, API Integration, Shopify API, GitHub, Serverless, JSON, SQL, HTML5, Object-oriented Programming (OOP), Zend Framework, Payment APIs, Dashboards, Admin Panels, Chart.js, Laravel

Gift Cards and Cart and Checkout Modules
I needed to build the cart and checkout pages and a gift card module for a large eCommerce business using React/Redux and following the best TDD practices.

• Existing checkout and cart pages were rewritten altogether, leaving the original design in place to align with the most modern web development practices using React/Redux.
• A large portion of code was cleaned up in order to provide the best re-usability together with improved site performance.
• Test-driven development was incorporated to achieve great code clarity for other developers working on the project (Jest and
•We also needed the gift card module registration to be viewable.

Viking Cold Calculator

An energy savings calculator application (built with Vue.js) for a company that produces cooling solutions.

• This application utilizes multiple APIs—Pardot, Google Tag Manager, Gravity Forms API, Acton, CouchDB, and Chart.js—and functions as a progressive web app by allowing users to work with it offline. Gathered data is then sent to the server immediately as the device regains an internet connection.
• I developed this custom solution to simplify the entire application by simply editing a CSV file with the translated strings of text.
• The app functions equally well across all devices and through a kiosk app on tablet devices.

Resume Website
The project is my resume website built with React and Redux that incorporates fully custom code and design.

• Each section of the application is a widget with its design and functionality, which leads to a high degree of interactivity and a nice-looking web page that is a pleasure to use.
• A Fullpage.js plugin was modified to provide a custom parallax effect on each section scroll. Each section offers a smart way to display a large amount of information tightly restricted by the viewport borders.

Animation Techniques:
• HTML canvas with JavaScript image processing
• CSS animations and CSS transitions—each technique is optimized to ensure that visual-rich application is as responsive and smooth as possible

Automated Insights

A marketing website for the digital data processing agency which is full of visual animations and fancy transitions.

• It incorporates a custom-built alert system, which utilizes Google Maps geocoding to display alerts relevant to the user and complex mouseover effects to play videos forward and backward depending on the cursor position within the alert box.
• I developed custom pagination for the blog system, which allows one to add multiple blog sections to a page which will all be under the control of the browser history API—loading the content via Ajax for the smoothest user experience.
• The system allows the user to add data-to-text transforming animations easily to any title on the website and the ability to switch the entire look of the website via an option in the admin panel.

Hacker News Reader App
An app that fetches the most recent posts from the Hacker News platform.

• One thing that distinguishes this app from similar ones is that posts are displayed as soon as each one is fetched—not the whole bulk. This improves the interactivity of the app compared to similar solutions.
• Another feature of the app is that it works offline by utilizing the IndexedDB API.
• Custom filters at the top right and infinite scroll make this app a pleasure to use.

Frogger Game Clone
A famous game clone built with vanilla JavaScript using the best practices of object-oriented programming.

• I composed all of the code myself, covering all aspects of the application; this included requesting frames and ensuring that the app runs at 60 FPS to manage all objects' position, movement, and collisions.
• I further customized the initial concept to include difficulty levels defined by the obstacles, number of enemies, and their speed, as well as the ability to choose different characters and options to remove or reset obstacles with a single click of a button.
• The scoring system was introduced to add complexity to the application.

Twitter Bot
A PHP application that utilizes the Twitter API and displays formatted posts from a selected Twitter account in a selected visual.

• I set up a cron job on a server that executes the script that pulls tweets from a preselected account. It then formats the text from those tweets by removing images, emojis, links, and so on.
• The resulting text is then split into a certain amount of lines, and specific font size is applied for the message to occupy the container nicely. Finally, the text is plugged into an image containing the box for that text, and the result is published to the user's account.

Educated Body
A very design-centered website for an agency specializing in the gym and spa sector.

• Lazy loading was taken to the next level for this project to reach the smoothest user experience possible. Everything, including text, blocks, and images, appears in a certain way in a certain order to give this website a slick and structured feel.
• The existing plugins (a slick carousel) were customized to fit the client's needs to have the customized pagination behaving in a certain way. One section required two slick sliders to be tied together, resulting in complex logic and interactions which provide a very interesting user experience.
• A custom sticky sidebar on internal pages and very large font sizes were a challenge to overcome during the development of a responsive side of the website.
• I also added custom parallax effects to further enhance the visually pleasing nature of the website.


A React web application that was later rewritten with Vue.js for an organization providing local learning centers throughout the UK.

• The application is centered around a map created from a very complex set of data. Lower sets of data exceeded 1GB in size, so that data had to be optimized, simplified, split into logical chunks, and efficiently loaded so as not to impact load times too much.
• I used a React and React Router DOM for a smooth app feel, and all of the data is backed by a WordPress REST API (which I also developed from scratch to satisfy the client's needs).
• Later, the app was rewritten using Vue.js coupled with Vue router and Vuex for a better code organization following the best practices.

A marketing/booking website for a UK hotel business.

• Efficiently written scripts and CSS animations allow this app to be both visually pleasing and highly performant. The differences between mobile and desktop versions meant responsive challenges, which were gracefully overcome at the very early stages of the development, thanks to very good communication between design, management, and coding teams.
• A custom-written solution enabled a nice integration of the booking engine directly into the web page.

A large-scale eCommerce project which helped sign a contract with Walmart.

• I built with the Foundation CSS framework and PHP on top of WordPress back end and WooCommerce framework. The initial design has undergone many revisions that required careful planning for the website structure as well as CSS and JavaScript code, to make sure that this doesn't lead to a messy project.
• The checkout page is a completely custom solution that uses the best object-oriented practices and matches the complex requirements of the Walmart team.


A landing page and a React web application for an industry-changing car leasing platform in the USA.

• A landing page with a beautiful custom parallax effect for a maximum interactive experience for the user. A second version of the landing page was used for A/B testing via Google Tag Manager.
• A complex multi-step React application provides many ways for a user to find their dream car and make the leasing process as easy as possible for every client.

An auction house web application for finding great deals on cars; it was built using the Meteor framework.

• The application consists of a very complex filtering system that helps users find their car easier. It works well with multiple listing types such as buy-now, auction, reserved-price auction, etc.
• Multiple widgets, like a price calculator, were developed to guide users and help them make a much better decision.

Web3 Social Network Platform

This is a revolutionary social network platform built with Next.js and Ethereum blockchain. I took a CTO role to lead a team of highly skilled developers and architected a highly scalable system to serve millions of users.

From the technical side, I have chosen to utilize Prisma coupled with the PlanetScale cloud database and establish the link between the database, back end, and front end using tRPC for the absolute best type of safety and robustness of the application. We have utilized Vercel and AWS cloud service providers to have an entirely cloud-based platform, thus achieving the absolute best uptimes for the app.
2010 - 2014

Bachelor's Degree in Civil Engineering

University of Bath - Bath, UK


Front-end Web Developer Nanodegree



X (formerly Twitter) API, Flexbox, jQuery, Vue, Vue 2, React, Chart.js, React Router, Node.js, WordPress REST API, REST APIs, React Redux, Stripe, Stripe API, Stripe Connect, Shopify API, SQLAlchemy, Binance API, Google Maps, Web3.js, Backbone.js, D3.js


Webpack, PostCSS, Gulp, Slack, PhpStorm, WebStorm, Git, JSS, Mongoose, Sequelize, Babel, Prisma, Figma, MetaMask, NPM, GitHub, Stripe Checkout, Mocha, NGINX, Terraform, Auth0, Grunt, Photoshop 7, Jira


Vuetify, Redux, Jest, Cypress, Yarn, Svelte, Quasar, Next.js, React Native, Tailwind CSS, AngularJS, Draft.js, Express.js, OAuth 2, Zend Framework, Laravel, Django, Nuxt.js, Knockout (Knockout.js), Ruby on Rails (RoR), Electron, Flask, Angular, tRPC


PHP, GraphQL, Less, TypeScript, JavaScript, HTML, CSS, SCSS, SQL, HTML5, PHP 5, Python, Ruby


Functional Programming, Object-oriented Programming (OOP), REST, Agile, Test-driven Development (TDD), Jamstack, Application Architecture, Unit Testing, DevOps


WordPress, Mapbox, PlanetScale, Contentful, Shopify, AWS Lambda, Twilio, iOS, Android, Amazon Web Services (AWS), Amazon EC2, Visual Studio Code (VS Code), Linux Mint, WooCommerce, Linux, Firebase, Blockchain, Magento, Meteor, Google Cloud Platform (GCP), Ethereum, Vercel


Databases, MongoDB, MySQL, PostgreSQL, JSON, Redis, Amazon S3 (AWS S3)


Web Development, CSS Grid, Styled-components, Front-end Development, Front-end Architecture, ESLint, WebSockets, Infura, Ethers.js, Slate, TinyMCE, Cryptocurrency Wallets, API Integration, Front-end, Back-end, Lambda Functions, VoIP, MERN Stack, Technical Leadership, APIs, Full-stack, Architecture, Server-side Rendering (SSR), Serverless, Stripe Payments, Payment APIs, Dashboards, Admin Panels, ParcelJS, OpenStreetMap, QGIS, Squarespace, CTO, Smart Contracts, Software Architecture, Laminas, Polygon, Middleware, IPFS, Non-fungible Tokens (NFT), FOMO

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