Adrien Pélégris, Developer in Paris, France
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Adrien Pélégris

Verified Expert  in Engineering

Software Developer

Paris, France
Toptal Member Since
March 29, 2019

Since 2013, Adrien has been working with startups in their high-growth phases. He's delivered hundreds of React components and designed horizontally scalable back-ends supporting 100,000+ concurrent WebSocket connections using Node.js, HAProxy, and Redis cluster. He enjoys professional environments that support clear communication, quality, and ambitious goals. In his spare time, Adrien tinkers with IoT devices and deep learning models.


React, TypeScript, GitHub Actions, E2E Testing, Unit Testing, Storybook...
WebSockets, Kubernetes, PostgreSQL, Node.js, Redux, React, Figma, APIs, Swagger...
PepsiCo Global - Main
Django, React, Redux, D3.js, Material UI, TypeScript, APIs, Jest




Preferred Environment

Node.js, React, Webpack, ESLint, Visual Studio Code (VS Code), Git, Ubuntu

The most amazing...

...rewarding achievement I've had was to bootstrap a web app of a peer-to-peer lending startup and get hundreds of customers in less than three months.

Work Experience

Senior Front-end Developer

2022 - 2023
  • Designed and implemented the architecture of a new app: repository structure, routing, configuration management, choice of libraries (network querying and forms), quality processes (testing, code structure rules, lining, and formatting), and CI/CD.
  • Developed 100+ React components in TypeScript, handled end-to-end testing for complex and lengthy forms, and built reusable hooks logic.
  • Worked with two other junior front-end developers. Guided best practices and code quality. Led the back-end team to provide an OpenAPI specification from which front-end code was automatically generated.
Technologies: React, TypeScript, GitHub Actions, E2E Testing, Unit Testing, Storybook, OpenAPI, Google Cloud, APIs, Swagger, Jest, Architecture

Senior Full-stack Developer

2019 - 2023
  • Developed new front-end features in a complex React and Redux project for a financial platform (Zipmex), interacting with a third-party WebSocket gateway.
  • Improved performances (CPU consumption from 60% to 15%) of a front-end app after the re-render cycle analysis, using React Developer Tools and a deep understanding of the Redux rendering logic.
  • Developed new back-end services (REST API and bots) with Node.js, TypeScript, PostgreSQL, and Kubernetes.
Technologies: WebSockets, Kubernetes, PostgreSQL, Node.js, Redux, React, Figma, APIs, Swagger, Microservices, Jest, Architecture

React and Django Full-stack Developer

2020 - 2021
PepsiCo Global - Main
  • Developed an app to create and monitor marketing campaigns: sophisticated calendar of campaigns in React (supporting 100+ concurrent campaigns display) and data visualization for key metrics (budget, active campaigns, etc.).
  • Collaborated with a team of two other developers, one product owner, and one manager from Europe and America.
  • Participated in user demos and feedback sessions to improve the product.
Technologies: Django, React, Redux, D3.js, Material UI, TypeScript, APIs, Jest

Senior React and Full-stack Developer

2020 - 2020
Scarselli Diamonds Inc
  • Developed a React app (using the React-admin framework) to let users manage (CRUD) gemstones information with various user permissions.
  • Created a Node.js TypeScript API to support the gemstones management operations.
  • Set up the cloud environment to deploy the app and run the PSQL database.
Technologies: Full-stack, Software Architecture, JavaScript, Cloud, React, PostgreSQL, TypeScript, Figma, APIs, Architecture

Senior Full-stack Developer

2019 - 2019
  • Developed a new interactive loan application form for Lendico (German lending platform) that is fully responsive and provides better UX.
  • Re-factored the legacy codebase and mentored junior developers for coding best practices.
  • Worked closely with the product manager and QA engineer for fast iterations in a continuous integration pipeline (Kubernetes).
Technologies: REST APIs, Kubernetes, Vue, APIs, Jest

Full-stack Developer

2017 - 2018
24 Sèvres
  • Integrated graphic designs in CSS from Zeplin/Sketch.
  • Developed responsive front-end code for the product page of a high-quality eCommerce website (
  • Optimized the website to reduce load time.
  • Developed the back-end code in Symfony.
  • Designed back-end queues to communicate with other internal APIs.
Technologies: AWS ELB, Amazon S3 (AWS S3), Amazon EC2, Vagrant, Travis CI, Terraform, RabbitMQ, Symfony, PHP, Sass, Webpack, jQuery, JavaScript, React, APIs

Full-stack Developer

2017 - 2018
BNP Paribas
  • Developed React components.
  • Designed and developed API routes.
  • Wrote unit tests.
  • Hired and mentored junior developers.
  • Improved the DevOps pipeline (Jenkins/Rancher).
Technologies: Ansible, Jenkins, Rancher, Docker, Storybook, Styled-components, ECMAScript (ES6), Express.js, Node.js, React

Full-stack Developer

2016 - 2016
  • Developed a new front-end to increase the conversion rate.
  • Integrated new third-party APIs for payments and legal publications.
  • Resolved bugs and improved legacy and poorly-maintained code.
  • Contributed to the design of a new system to enable entrepreneurs to create their company with no human assistance.
  • Worked in a top-notch Scrum environment with one of the best companies using and improving Agile methodologies.
Technologies: jQuery, PHP, APIs

Lead Developer | CTO

2016 - 2016
  • Developed the whole front end from scratch and alone with just one designer. (Bootstrap, Material Design).
  • Set up the whole back-end architecture and DevOps.
  • Developed the back end that handled critical (personal and financial) information for loan applications.
  • Integrated MANGOPAY (virtual wallets) to manage fund transfers.
  • Gave and applied recommendations to start the business following a Lean approach (from 0 to hundreds of clients in three months).
Technologies: Amazon Web Services (AWS), Go, Amazon EC2, Amazon S3 (AWS S3), PostgreSQL, Node.js, ECMAScript (ES6), Webpack, Redux, React, APIs, Swagger, Microservices, Architecture

Full-stack Developer

2015 - 2016
  • Improved a back end supporting 1,000+ concurrent WebSocket connections to a horizontally scalable architecture supporting 100,000+ connections with Node.js and Redis as a cluster.
  • Designed and ran high-load testing scenarios with precise real-time monitoring with InfluxDB and Grafana.
  • Designed a new API between the client and the tracker to remove the useless coupling and decrease friction between teams.
  • Delivered Vanilla JavaScript code on the client-side in the peer-to-peer layer.
  • Developed two new microservices using Go to successfully explore the gains in performance (10x).
  • Designed and implemented monthly payment plans using Stripe.
Technologies: Go, Angular, JavaScript, Grafana, InfluxDB, Azure, Amazon Web Services (AWS), Redis, Node.js, APIs, Microservices, Architecture, Video Players


2013 - 2014
Genie Solutions Pty Ltd
  • Developed new features in the 4D environment.
  • Resolved bugs.
  • Developed a proof-of-concept for a single-page application using AngularJS.
Technologies: 4D, Angular, APIs

Full-stack Developer

2009 - 2013
  • Developed and maintained the geographic information system (GIS) to acquire and process digital maps containing natural and technological hazard data.
  • Built the server-side application in a Debian environment that processes the user's input (address), geolocation on the risks maps, OpenDocument generation, and pdf conversion.
  • Designed the databases (MySQL) containing customer information, prices, orders, bills, etc.
  • Developed marketing tools (mailing, CRM, and others).
Technologies: PHP, JavaScript, HTML, CSS, MySQL, PostGIS

Signal Processing Intern

2011 - 2012
  • Designed new beamforming filters for the smart office phone with mentoring and support from a senior engineer.
  • Created and developed a distortion monitoring test for the QA in a factory in China.
  • Ran sweep frequency response tests in the anechoic chamber to establish a profile of the smart office phone.
Technologies: C, Git, LabVIEW, MATLAB

This is a site for microloans funded by individuals.

24 Sèvres
An eCommerce website for fashionable clothing.

Offload the video CDN to a peer-to-peer network of viewers through WebRTC.

Loan Application Form for Lendico

A fully-responsive web app with improved UX to increase the conversion rate of loan subscriptions. Highlighting parts of the form when scrolling helps users not to feel overwhelmed by the amount of input required

Web App for Financial Platform (Zipmex)

A web app to let users see trades, orders, wallets, settings, and more.
It is a complex web app due to the highly interactive nature of the business.
It supports internationalization (English, Bahasa, Thai).
2012 - 2013

Master of Engineering Science (Management) Degree in Biomedical Engineering

The University of Queensland - Brisbane, Australia

2009 - 2013

Bachelor's & Master's Degree (in Agreement with the University of Queensland) in Computer Engineering

École Centrale Paris - Paris, France


Node.js, React, Socket.IO, WebRTC, jQuery, Vue, REST APIs,, TensorFlow, NumPy, D3.js, OpenAPI


JavaScript Testing, Git, Webpack, Grafana, MATLAB, LabVIEW, RabbitMQ, Terraform, Travis CI, Vagrant, Ansible, Jenkins, AWS ELB, Figma


Redux, Swagger, Bootstrap, Express.js, Jest, Angular, Symfony, Django, Material UI


HTML, JavaScript, CSS, TypeScript, SQL, GraphQL, ECMAScript (ES6), C, Sass, Go, PHP


Agile Software Development, Microservices, E2E Testing, Unit Testing


Redis, MongoDB, InfluxDB, PostgreSQL, MySQL, Amazon S3 (AWS S3), Google Cloud, PostGIS


Docker, Ubuntu, Amazon EC2, Amazon Web Services (AWS), Azure, Kubernetes, Rancher, Visual Studio Code (VS Code)


APIs, Full-stack, Google Material Design, Redis Clusters, Computer Vision, Architecture, ESLint, 4D, Styled-components, Storybook, WebSockets, Machine Learning, Engineering, Software Architecture, Cloud, GitHub Actions, Video Players, Image Processing, Apps

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