Andrei@Constantinescu.io
andrei@constantinescu.io

Summary

JavaScript Consultant with 10+ years of experience creating scalable web apps and intuitive interfaces using React, Next.js, and Node.js. I've developed microfrontend bridges for mobile apps, engineered a personal privacy-focused service network, and currently building a fitness app powered by React Native. When I'm not fine-tuning my custom LLM or at the gym, I'm delivering impactful solutions. Open to both short-term and long-term roles where I can make an immediate impact.

Skills

Highlights

contractCitibank UK(Financial)
React Front End Developer
Apr 2025 - Current
  • Rebuilt critical UI components for commodities trading workflows using modern React patterns and ag-Grid's latest version, delivering a 35% faster, more responsive interface with complete feature parity.
  • Architected performant React components with optimized rendering strategies for real-time market data, reducing unnecessary re-renders and significantly improving application responsiveness under high-frequency updates.
contractBalyasny Asset Management LLP(Financial)
UI Developer
Oct 2022 - Dec 2023
  • Built internal trading analysis tools using ReactJS, NextJS, GraphQL, and Ag-grid, improving interaction speeds by 25% and reducing bundle size by 20%.
  • Contributed to a centralized monorepo, simplifying maintenance and ensuring consistent code and UI quality.
contractBP plc(Energy)
software consultant
Mar 2020 - Mar 2021
  • Developed a framework-agnostic Payments SDK in TypeScript with 90% test coverage and built a ReactJS sandbox app to ensure reliability across payment scenarios.
  • Enhanced security by implementing an AWS-based user login monitor with automated alerts and notifications.
contractPartners Capital LLP(Financial)
frontend developer
Sep 2019 - Mar 2020
  • Developed a ReactJS and TypeScript application, replacing Excel-based processes and improving responsiveness by 35% through optimized state management.
  • Implemented an end-to-end testing regime with Cypress, ensuring feature reliability and system integrity.

Previous

  • contractUnlikelyAIUI DeveloperApr 2024 - May 2024
  • contractCMC Markets plcsoftware consultantJul 2021 - Sep 2022
  • contractKaluzasenior frontend developerJun 2019 - Sep 2019
  • contractNowTV (Sky UK)senior developerNov 2018 - May 2019
  • contractuSwitchsenior frontend developerAug 2018 - Oct 2018
  • contractThe Sun (News UK)full stack developerMar 2018 - Aug 2018
  • contractAIGfrontend developerNov 2017 - Feb 2018
  • contractThird Space Learningfull stack developerAug 2017 - Oct 2017
  • permanentBeamlysoftware engineerNov 2016 - Aug 2017
  • permanentKano Computingsoftware engineerJul 2015 - Oct 2016
  • permanentLearn Forwardsoftware engineerApr 2014 - May 2015

Key Highlights

BSc in Computer Science from University of Bucharest
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