Lewis Mills

Coach Yu is an iOS + Apple Watch app for Olympic weightlifting athletes and coaches, combining hardware-free velocity-based training (VBT), real-time bar path tracking, and AI form analysis in a single product. Co-founded with a British national weightlifter — a two-person team, with me leading engineering. Currently in closed beta with invited coaches and their athletes — with a full public launch planned once the Android client is ready.

• Directing engineering and product priorities across mobile, backend, and AI, as one of two co-founders
• Built and shipped native iOS and watchOS apps in Swift/SwiftUI, including a companion Apple Watch experience with live workout tracking, synced rest timers, and heart rate monitoring
• Built real-time, on-device bar path tracking and video overlay during recording, plus a server-side AI pipeline for per-phase form scoring across six lifts, including the competition lifts and key variations, completing in ~15-20 seconds per video — replacing a barbell-mounted VBT sensor
• Ran the deeper form-scoring AI server-side, giving every user the same scoring accuracy regardless of device — a decision that also shaped starting iOS-first, since its hardware range was narrower and more predictable than Android's
• Designed and built a Go backend on Google Cloud Platform to serve program data, workout logs, and video uploads, calling out to a Python service that runs the computer vision and form-scoring models
• Built the full training program system: coach-assigned programs, structured phases/weeks/sessions, adaptive weight progression for free-form training, and an AI performance dashboard tracking form and velocity trends over time

Currently building: Android client in Kotlin, bringing the full feature set to a second platform

• Full-time caregiving responsibilities, prior to starting Le Wagon

Le Wagon final project, built by a team of 4. As the most experienced developer on the team, I acted as repo owner and integrator — merging the majority of the team's pull requests — while also building most of the frontend.

• Merged most of the team's pull requests (PRs #3–#65, 67 of 152 total commits) as de facto repo owner, alongside setting up the initial Rails/Devise scaffold and CI workflow
• Built the jobs feature end-to-end: index and show views for both job-seeker and business sides, the new/edit forms, and the underlying Job model
• Built the dashboards for both user types (job-seeker and business)
• Built the Devise auth views — sign-up, sign-in, account editing — plus the shared navbar, footer, home page, and about page
• Wrote the majority of the SCSS styling across the app, including the homepage, navbar, and both dashboards
• Made backend contributions too, including the resumes controller, schema changes, and the Heroku deploy

A mobile banking app prototype: SwiftUI/SwiftData on iOS, backed by a Go server for auth and account data.

• Built a full-featured iOS banking app UI in SwiftUI covering transfers, savings pots, direct debits, transaction history, and overdraft management
• Implemented MVVM architecture with ObservableObject view models, Combine for reactive state, and SwiftData for local persistence
• Built a Go server for authentication and account data, called from the app over async/await networking with JSON decoding
• Designed a custom UI/asset system in Assets.xcassets for a bespoke visual identity distinct from stock iOS components

This Coach Yu–styled CV prototype, built with React and Next.js, including a live-editable easy read mode for accessible typography, spacing, and contrast.