Weili Dai - Full Stack Developer

Weili Dai

Tech Lead - Full Stack Developer

I craft end-to-end solutions with 10+ years of experience building scalable applications and leading development teams.

Previously Tech Lead at Gumtree and worked at CNN, Sky, BBC

JavaScriptReact.jsTypeScriptReduxWebpackEmotionCSS-in-JSSCSSStorybookReact SSRNode.jsExpress.jsRESTful APIsJavaScalaJenkinsDockerKubernetesGCPAnsibleBigQueryPostgreSQLMongoDBRedisMSSQLTDDJestReact Testing LibraryCypress

Frontend Development

  • Modern React Architectures
  • Performance Optimisation
  • Responsive & Interactive UIs
  • Third-party Integrations

Backend Development

  • React Server-Side Rendering
  • API Design & Development
  • Legacy Code Migration
  • Monitoring and Alerting

DevOps & Cloud

  • Scalable Architecture
  • CI/CD Pipelines
  • GCP Infrastructure

Enterprise Projects

Rebuild Legacy Service with React + TypeScript

  • • Rebuilt monolithic Java/FreeMarker templates into modular, testable components using React, TypeScript, and Emotion.
  • • Pages served over 1M requests per day; I owned the entire rebuild across architecture, testing (Jest), and rollout.
  • • Created frontend patterns now adopted across the org, enabling consistent design and faster onboarding.
  • • Optimised SSR performance and browser load with backend profiling and selective lazy loading — improving core metrics by 30%.
  • • Engineered a new CI/CD process that automated production deploys, removing prior dependencies on Platform and enabling 10x deployment frequency.

Key Outcome:

Full re-architecture of critical web pages — both frontend and DevOps — driving lasting team-wide impact.

Partnerships API Server

  • • Full ownership of high-throughput Node.js backend powering in-house ads across web and mobile.
  • • Designed and implemented an API server from scratch using Node.js
  • • Served both website and native apps, handling 200+ RPM
  • • Delivered business-critical ad placements across pages
  • • Owned DevOps: Jenkins CI/CD, deployed via Google Cloud Kubernetes
  • • Handled data flow design, endpoint structure, and monitoring

Key Outcome:

End-to-end system delivery — from architecture to deployment — at production scale.

Scala to TypeScript Migration

  • • Backend logic refactor to unlock team-wide maintainability and cross-functional collaboration.
  • • Migrated core AdTech config system from Scala (backend) to TypeScript
  • • Reverse-engineered complex business logic and functional patterns
  • • Enabled frontend developers to contribute to what was once Scala-only code
  • • Reduced bottlenecks and dependency on backend specialists

Key Outcome:

Turned isolated backend logic into maintainable shared code — boosting team velocity.

Pricing DB Workflow Automation

  • • Transformed a manual SQL-driven process into a safe, automated backend system.
  • • Original workflow involved handcrafted SQL + live production DB changes
  • • Only expert backend engineers could manage updates safely
  • • Built a tool allowing pricing managers to upload a CSV to apply updates
  • • System handles validation, parsing, transformation, and safe execution
  • • Built supporting infra and CI pipelines to deploy securely

Key Outcome:

Converted a risky, engineer-only flow into a robust tool for non-technical users.

Let's Build Something Amazing

Looking for a full-stack developer who can architect and implement complete solutions? Let's discuss your project.

London, UK
Get in TouchView CV