Fitness app development
Software for gyms and trainers, from the team that runs GymFast.
Acasa Labs builds fitness software: gym management platforms, branded member apps, apps for personal trainers, and workout apps for consumers. We also make GymFast, our own gym management product with a web dashboard and apps for staff, members, and trainers. You can use GymFast, or have us build your own product on the same foundations.
The problem
A gym runs on renewals, and renewals run on memory.
Most gyms and trainers run members, plans, payments, and follow-ups from spreadsheets, WhatsApp, and someone's memory. A renewal date slips, an enquiry is never called back, a trainer's plans live on paper. Every one of those is revenue walking out the door. Generic software helps a little, but it rarely fits how a particular gym, studio, or coach actually works.
What we build
- 01
Gym and studio management
Members, plans, invoices, expenses, classes, attendance, and enquiries in one dashboard, for one location or many.
- 02
Branded member apps
An app in your gym's colors where members check in, follow their workout and diet plans, log sessions, and see their invoices.
- 03
Apps for personal trainers
Clients, plans, session scheduling, workout logging, and invoices, for coaches who work on their own or inside a gym.
- 04
Consumer fitness apps
Workout and habit apps with plans, logging, streaks, and subscriptions, on iOS and Android from one codebase.
From production
What we learned building GymFast.
Reminders that send themselves
GymFastRenewal, payment, class, and session reminders, plan expiry, enquiry follow-ups, and auto check-out all run on a schedule as edge functions, so staff stop chasing and the gym does not depend on someone remembering.
One platform, three apps
GymFastStaff, members, and trainers each get their own app, on a token-authenticated mobile API shared with the web dashboard. Each app shows only what that person needs.
The gym's brand, not ours
GymFastEach gym's brand colors theme the web dashboard and the mobile apps from one setting, so members open an app that looks like their gym.
Built for the gym floor
GymFastGyms have bad signal. An in-progress workout is saved on the device, so a dropped connection mid-session does not lose it.
Honest trade-offs
Use GymFast, or build your own?
If you run a gym or a training business and want the software running this month, use GymFast. It already does members, billing, classes, reminders, and branded apps. Build your own when the product is the business: a fitness startup, a chain with its own way of working, or a coaching program that needs features no gym software has. We do both, and we will tell you honestly which one fits.
What we reach for
- Expo, React Native
- Next.js
- Supabase Postgres with row-level security
- Supabase Edge Functions, Realtime
- RevenueCat
- Turborepo
Proof
Shipped, not pitched.
01Our product
GymFast
Members, billing, classes, and workout plans for a gym, in one platform and three apps.
Gym management software for gym owners and personal trainers. A web dashboard and a staff app run members, plans, invoices, enquiries, and classes; members get their own branded app; GymFast Pro gives independent trainers the same tools for their clients.
Web dashboard · iOS · Android · Staff, member, and trainer apps
Questions
Fitness questions we get asked.
Can you build a custom app for our gym chain?
Yes. We can build on the same foundations as GymFast, with your brand, your membership rules, and the integrations you need, so you start from a working base instead of a blank page.
Do you build workout apps for consumers?
Yes: workout plans, logging, progress, and subscriptions on iOS and Android. GymFast's member app already has plans, logging, and offline saving, which are the hard parts.
Can members pay inside the app?
Yes. For digital subscriptions, Apple and Google require in-app purchase, which we handle with RevenueCat. Gym memberships paid in person or online can be invoiced and tracked in the dashboard.
Can personal trainers use it without a gym?
Yes. That is what GymFast Pro is: clients, workout and diet plans, session scheduling, logging, and client invoices for independent coaches.
Who owns a custom app you build for us?
You do: the code, the store accounts, and the data. GymFast is our product; a custom build is yours.
Can the app work offline in the gym?
Yes, for the parts that matter on the floor. GymFast saves an in-progress workout on the phone and syncs it when the signal comes back, and we design custom builds the same way.
Can it send reminders on WhatsApp or SMS?
In a custom build, yes, through the WhatsApp Business API or an SMS provider. Reminders run on a schedule, so nobody has to send them by hand.
Fitness app development
Running a gym, or building a fitness product?
Tell us which. We will show you GymFast, or scope the product you want to build.