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DS Coaching

A web app for a personal trainer and their clients: plans, workouts, check-ins and progress in one place. Almost 100 active users.

Visit the site

Reserved for the trainer's clients: you can't get past the sign-in.

Role
Design and development, solo
Year
2026
Stack
Next.js, Supabase, PWA
Screens of DS Coaching

The context

A personal trainer followed clients with PDF plans sent over WhatsApp, check-ins by voice and notes on paper. Writing or changing a plan took hours.

What I built

I built a web app that installs on the phone, with two sides. The trainer manages clients, plans and a library of reusable exercises. The client sees the day's workout, logs sets and weights, checks in and follows their progress.

How it went

It is in use with almost 100 active users, and the trainer saves hours on building plans.

Technical deep dive

Next.js and Supabase. It is a PWA that also works offline: workouts logged without a connection sync once it comes back.

It handles health data, so it is built around GDPR: a data protection impact assessment (DPIA), a record of processing, explicit consent and account deletion on request.

Sign-in protected by CAPTCHA (Cloudflare Turnstile) and BotID, rate limits on requests and a security audit before release.

Set up for PostHog, with data kept in Europe, to understand how it is used.