Weili Dai

Technical Skills
  • Frontend: JavaScript, React.js, TypeScript, Redux, Webpack, Emotion, CSS-in-JS, SCSS, Storybook
  • Backend: React SSR, Node.js, Express.js, RESTful APIs, Java, Scala
  • DevOps/Cloud: Jenkins, Docker, Kubernetes, GCP, Ansible
  • Databases: BigQuery, PostgreSQL, MongoDB, Cassandra, Redis, MSSQL
  • Testing: TDD, Jest, React Testing Library, Cypress, Mocha, Sinon
Languages
  • English - Native
  • Chinese - Fluent
About Me

I’m a Full Stack Tech Lead with over 10 years’ experience building robust frontend systems using React CSR/SSR, Redux, TypeScript, and Node.js.

Currently leading Frontend UI and AdTech initiatives on a platform reaching 35 million monthly sessions.

I'm passionate about collaboration with cross-functional teams, mentoring developers, and creating high-quality scalable code whilst taking advantage of the latest opportunites offered by AI.

My technical expertise spans both backend and frontend React/TypeScript, and DevOps skills such as Jenkins, Docker, and GCP.

I hold a PhD and a first-class degree in Computer Science and Electronics, both from Imperial College London.

Work Experience
Frontend Tech Lead – Gumtree May 2017 – Present
  • Tech Lead for Buyer Team, overseeing SEO initiatives driving 35 million monthly sessions, site reliability, and ongoing enhancements.
  • Led AdTech Team's integrations with other advertising platforms (such as GAM, Bing Search Ads, AdSense, etc.) and other third-party integrations (Permutive, Google Analytics, Tag Manager), establishing a streamlined, maintainable integration templates.
  • Migrated legacy Java/FreeMarker systems to TypeScript/JavaScript using React (CSR/SSR) and Redux, improving development speed and maintainability.
  • Mentored junior developers, successfully supported them to promotions, developed onboarding documentation.
  • Optimised site performance using Lighthouse and SpeedCurve analytics.
  • Enhanced Jenkins CI/CD pipelines with parallel builds and improved UI, significantly reducing wait times and aiding operational teams.
  • Rebuilt ad integrations from Scala to TypeScript, enabling easier self-management and reducing operational overhead.
  • Modernised codebases using TypeScript, React Hooks, Emotion CSS-in-JS, leveraging AI assistance.
  • Increased unit test coverage from 30% to 60%, migrating tests to React Testing Library for React 18 and Webpack upgrades.
  • Managed multiple full-cycle projects, temporarily stepping into Backend (Java) and Product Management roles; facilitated effective cross-team collaboration.
  • Introduced Cypress for test automation, implementing efficient Jenkins CI/CD workflows with enhanced reporting capabilities.
Senior Software Developer – CNN Nov 2016 – Apr 2017
  • Migrated CNN News site from PHP to React CSR+SSR with modern routing and Redux setup.
Software Engineer – Sky Sep 2015 – Nov 2016
  • Built full stack Node.js systems for a sports ticketing platform.
  • Acted in a DevOps role to set up Jenkins CI/CD pipelines and improve build times.
  • Acted in a SiteOps role to set up cloud infrastructure using Ansible on OpenStack (similar to AWS) to enable automatic scaling and cost optimisation.
Software Engineer – BBC Oct 2013 – Sep 2015
  • Built Java/Scala backend for core CMS systems used by BBC journalists to upload news articles on to the BBC News website.
Education
PhD in Design Engineering2010 – 2013 Imperial College London
MEng in Computer Science & Electronics2006 – 2010 Imperial College London, First Class