Senior UI Developer
William Hill — Betslip & High-Impact UI Engineering
Led front-end development, resilient component architecture, and high-impact A/B testing campaigns for a legacy British sports betting giant handling millions of daily active users.
The Role
Betslip Squad Core
Dedicated UI Developer on the Betslip squad — a cross-functional Agile team of nine people. Responsible for building, maintaining, and evolving the React-powered Betslip module at enterprise scale.
Critical UI Engineering
Resiliently built and evolved the Betslip — the most business-critical UI component where users place bets, review odds, and commit money. High pressure, defensive engineering.
Front-End Testing & QA
Wrote unit tests with Jest and Enzyme to validate component behavior, and end-to-end integration tests using Cypress. Managed deployments via GitLab CI/CD pipelines.
Optimizely A/B Testing
Developed A/B test variants in Optimizely targeting key conversion touchpoints within the betting flow, delivering measurable conversion lift for millions of daily active users.
Visual Evidence & UI Prototypes
Live recordings of the betslip module, visual debug logs, and custom micro-animations.
Betslip Module in Action
A recording of the live sports betslip module showing selection states, stake placement validation, and live odds updating dynamically.
Betslip Card & Layout
High-fidelity screenshot of the betslip card displaying single, multiple, and system bet layouts, engineered for optimal readability on mobile screens.
UI Rendering Bug Fix
Analyzing a visual collision bug in the betslip card footer where absolute elements overflowed container bounds. Resolved by fixing flex layouts and z-index contexts.
Betslip Micro-Animations
Custom transition animations implemented using CSS and React lifecycle hooks to provide immediate, delightful visual feedback when users add, remove, or modify bets.
Case Study Under Construction
Detailed A/B testing frameworks, React component optimization techniques, and responsive design systems for sports betting platforms are currently being curated. Under construction — full experience coming soon.
Explore Other Topics //
- Cloudflare Experience Pioneering AI-driven web production and global deployment automationsview case study →
- Capgemini Experience Redesigning enterprise systems and guiding UX/UI design processesview case study →
- 💡 Pro Tip Ask Agent Lionz:
"What React components and A/B tests did Pedro build at William Hill?"
