Universal
Labs.AI engineers · London
WorkCase study · 05 of 08Coaching app

A fitness coaching platform.
For clients and their coach.

Built by Balmer combines a client fitness app with an administration panel for coach Matt Balmer. Clients access training, nutrition and check-ins in one place. An AI plan engine drafts personalised programmes using Matt’s coaching method, with every plan reviewed and approved by him.

Client
Matt BalmerClient · founding coach
Stages we ran
01Research
02Product
03UX & UI
04AI engineering
05Ship & run
Stack
Next.js · Supabase · Claude · Stripe · Vercel
Year
2026
Built by Balmer homepage
The problem

Supporting more clients with a consistent coaching service.

Training plans, nutrition guidance and client check-ins were spread across spreadsheets and messaging apps. The platform brings these tasks together, reducing administration while keeping the coach involved in each client’s programme.

ConstraintDeliver within the agreed scope and three-to-four-week schedule. Keep calculations and safety limits in code, with the coach approving every generated plan.
What we built

A client app, coach dashboard and planning engine.

01 · 03

The interview

Interviews with Matt established his coaching approach, planning rules and review process. An agreed rules document became the basis for the engine and its tests.

01 Research02 ProductRules Matt signed off
Built by Balmer — The interview
02 · 03

The plan engine

Code handles nutritional calculations, portions and safety limits. AI selects foods and exercises within those rules. In benchmark testing, this approach improved rule adherence from 68% to 97%. Matt reviews each plan before it reaches a client.

04 AI engineeringMaths in code, choices in the model68% → 97% on the bench
Built by Balmer training design: daily schedule, exercise logging and Today, Meals, Progress, Levels and Coach navigation
03 · 03

Two apps

Clients access sessions, meal plans, check-ins and coach messages through a mobile interface. The administration panel brings client progress and plan reviews together, with Stripe handling subscriptions.

03 UX & UI05 Ship & runClient app + admin panel
Built by Balmer — Two apps
Built withNext.jsSupabaseClaudeStripeVercel
Project outcomes

A live coaching platform, delivered to an agreed scope and schedule.

3 – 4 weeksAn agreed scope and fixed price, with weekly progress reviews.Scoped
97% rule adherenceThe plan engine on the bench, once the maths and safety moved into code.Measured
1,100+ test filesVitest across the client app, the admin panel and the engine's logic.Green