Build series · Introduction
What we’re building.
I’m building a web and mobile app for my friend Benji, and documenting the decisions, work and problems along the way.
By Ahmed Gadir3 min read
We’re building RepGarden, an app for personal trainers and their clients: trainers manage their work on the web, and clients use a mobile app to follow their training. A little vegetable mascot will grow stronger as they train, adding some fun to their progress.
My friend Benji
Personal trainer & strength and conditioning coach
My friend Benji is a personal trainer, and he’s agreed to be the first person we build this for. We’ll use his feedback as we design and build it, while making something other trainers can use too.
What the build will cover
We’ll explore the building blocks behind modern SaaS products: accounts, private user data, bookings, payments and the systems that connect them. We’ll take the product through testing, web deployment and approval on both mobile app stores.
I’ll also build an AI content pipeline: a repeatable process that generates exercise content, takes it through review and delivers approved material to the app. That’s a workflow you can adapt to other kinds of content.
Follow the decisions, not just the code
An AI coding agent will help write the code. I’ll explain how I direct it and check its work, including how to:
- Direct the AI with useful project context and focused requests.
- Understand your app’s architecture: how its parts fit together.
- Describe what should happen when someone uses the app.
- Read test results and check whether they demonstrate the expected behaviour.
- Investigate a problem and guide the AI towards a fix.
We’ll explain the technology and why we’re choosing it as we go. You’ll see designs, project documents, test evidence and the app itself as they develop.
Use what you learn
The public repository will show the project as it develops. Use the explanations to understand the work, try an idea or inform a project of your own.
AI won’t get everything right. I’ll share the checks, failures and fixes as well as the working results. The aim is to show what building a real product involves.
Benji on Instagram
He helps combat sport athletes get stronger, faster and harder to break.
Visit @benjamin_yr ↗Profile captured 19 September 2026.