NoticePinned · Oct 6
Thanksgiving: open 8 AM to 2 PM
Evening classes move to Friday. Your coach adjusts your plan.
Octavio Serpe · Co-founder & CTO, Kaizer
Be the gym nobody wants to leave.
Your members get an app with your name on it. Your team gets one place to run classes, check-ins and payments, with an AI assistant that does the admin.
Pilates, yoga, boxing or barre. Classes with capacity and waitlists, memberships your way, and an app with your studio's name on it.
AI builds the programs, loads adjust after every session, and your clients log every set in their own app. You get to coach.
In San Francisco Oct 13–25 ·
- Coaches on Kaizer
- 1,200+
- Gyms in Argentina
- 100+
- App Store
- 4.9
- Live in
- 3 days
- 1,200+ coaches on Kaizer
- 20+ countries
- 100+ gyms in Argentina
- 4.9 on the App Store
- 2,900+ reviews
- 76 AI assistant actions
- Live in 3 days
- Payments on Stripe Connect
- MCP for Claude, ChatGPT and Gemini
- Kaizer API for builders
- English · Español · Português
Kaizer for gyms and studios · Try it
Your app. With your name on it.
Type your name, pick what you run and a color. This is the app your members open every day.
What do you run?
Two ways to ship it
Inside the Kaizer app
IncludedMembers join your gym and the app takes your logo and colors.
Your own app
+$99/moYour name on the App Store and Google Play. We build and publish it.
@alex.rivera
12
YG
Training atYour GymMarina, San Francisco
News
See allClass
New: Barbell Club on Saturdays
Starts this week at 9 AM. Book it in the app.
Your bookings this week
See allYour workout
@alex.rivera
My bookings
@alex.rivera
12
Active routine1 of 2
Full Body Gym
Week 2 of 4 · 3 sessions per week
25% complete
Your sessions
Nutrition
Today1,480 kcal leftPlan by your coach
Protein78 / 160 g
Carbs75 / 250 g
Fat30 / 75 g
BreakfastGreek yogurt, oats, berries520
SnackBanana, whey shake350
LunchChicken, rice, greens720
Back squat · top set
225 LB
+40 lb in 8 weeks
Classes per week
5 THIS WEEK
+3 since you joined
@alex.rivera
News
My duesDue soon
Your Gym
$149USD / month
Due Saturday, Oct 10
NoticePinned · Oct 6
Thanksgiving: open 8 AM to 2 PM
Evening classes move to Friday. Your coach adjusts your plan.
Class
New: Barbell Club on Saturdays
Starts this week at 9 AM. Book it in the app.
Coach DaniOnline · your coach
Access · Your GymCheck in
New code in 10s
Membership activeDoor opens on scan
Tap around · try the check-in
Access control · built in
No pay, no entry.
The door checks dues on every check-in. QR, face or fingerprint, with the hardware you already have.
Sofia M.
Access granted
- 6:02 AMSofia M.FaceIn
- 6:01 AMLucas G.QRDenied
- 6:01 AMEmma C.FingerprintIn
Dues checked at the doorand on every booking
One day on Kaizer
From the first check-in to lights out.
What a day at your gym looks like when the software does the admin. Scroll through it.
6:00 AM · Doors open
Check-in takes a second.
Rotating QR, face or fingerprint. Dues get checked at the door. No pay, no entry.
Front desk · sample data
- SMSofia M.Active · FaceIn
- LGLucas G.Dues overdue · QRDenied
- JKJordan K.Active · QRIn
- ECEmma C.Active · FingerprintIn
7:30 AM · First class for a new face
Trial today. Member tomorrow.
Offer trial classes to people who aren't members yet, and see who joins after.
Trial classes · this month · sample data43% joined
MPMia P.Trial · Sunrise Vinyasa · 7:30 AMChecked in
Not just classes. If it has a schedule, it books.
- Classes
- Trials
- Nutrition consults
- Personal training
- Assessments
- Physio
12:15 PM · Lunch break
Don't ask AI. Put it to work.
Text or voice. 76 actions across members, classes, programs and payments.
Kaizer AssistantLive demo
Who hasn't come in for 2 weeks?
members.search({ lastCheckIn: ">14d" })12 members haven't checked in for 2 weeks or more. 4 of them renew this month. Send them a note from their coach?
5:45 PM · Peak hour
Coaches coach. Kaizer does the math.
Members log every set. The next session's loads adjust on their own, and coaches approve.
Back squat · set 3 of 3Member app
Weight185lb
Reps5target met
RIR2reps in reserve
Log the set and Kaizer sets the load for next session.
9:00 PM · Lights off
The report is already done.
Dues collected, reminders sent, and an alert for every member about to drift away.
Check-ins by hour · sampleTodayLast week
- Dues collected
- $3,480
- Reminders sent
- 7
- Members at risk
- 3
Smart alert: 3 members haven't come in for 14 days.
Kaizer for gyms & studios
Your gym, your rules.
Twenty things your team and your members get from day one. No add-ons.
Included in every plan
Hover or tap for details
Loads updated12 clients after today's sessions
+2 clients a monthaverage for coaches on the marketplace
Kaizer for coaches
Be the coach your clients remember.
AI programs, every client tracked, payments handled.
- AI programs
- Auto progression
- AI nutrition
- Client app
- Chat and voice notes
- Billing
- Marketplace
- AI assistant
- Gym mode
14-day free trial, no card · plans from $5/mo
Pricing in USD
Every feature in every plan.
You pay by members. Admins and coaches are free, and so is the app for your members.
You pay by active clients. Your clients use the app for free.
BoutiqueYour fit
$39/mo
Billed $468 a year
Up to 50 members
ClubYour fit
$100/mo
Billed $1,200 a year
51 to 250 members
GoldYour fit
$159/mo
Billed $1,908 a year
251 to 1,000 members
Over 1,000 members? We'll put together a custom plan. Book a call and we'll size it.
Your own app on the App Store and Google Play+$99/mo
BasicYour fit
$4/mo
Billed $48 a year
Up to 3 clients
- Routines by hand
- Nutrition
- Assistant · 15 messages a day
StarterYour fit
$16/mo
Billed $192 a year
Up to 15 clients
- Routines with AI
- Nutrition
- Assistant · 50 messages a day
ProYour fit
$41/mo
Billed $492 a year
Up to 50 clients
- Routines with AI
- Nutrition with AI
- Assistant · 200 messages a day
- Support in under 8 hours
ArnoldYour fit
$124/mo
Billed $1,488 a year
Up to 500 clients
- Routines with AI
- Nutrition with AI
- Unlimited assistant
- Support in under 8 hours
3 daysFrom sign-up to live
$0Setup fee
IncludedData migration and team training
14 daysFree trial, no card
14 daysFree trial, no card
FreeThe client app, for every client
IncludedChat and groups, payments, alerts and retention metrics
MarketplaceA public profile so new clients find you
The platform
Everything a gym runs on. One platform.
Apps, payments, email, your data and an API, white-label from day one. I lead the engineering behind it.
- Mobile appsMember app on iOS, Android and the web. Staff app for iPhone and iPad.
- White labelYour logo and colors, or your own app in the stores.
- PaymentsDues on Stripe Connect, reminders, and no pay, no entry.
- Email and pushReceipts, reminders and announcements, sent for you.
- Your dataEvery member, visit and payment, isolated per gym and exportable.
- APIBuild your own interface on the same API we use.
- MCPRun your gym from Claude, ChatGPT or Gemini.
- AI assistant76 actions, by text or voice.
Request path · sample traffic
38 req/s
Member app, staff app and admin web call the Kaizer API, which uses Postgres, events, payments and the AI assistant.
kaizer / stack
- Language
- TypeScript, end to end
- Mobile
- React Native + Expo, shipped with EAS
- API
- Node.js on Google Cloud (Cloud Run, Firebase Functions), hexagonal architecture
- Data
- PostgreSQL on Supabase + Drizzle, row-level security per gym
- Events
- Pub/Sub fan-out with idempotent consumers
- Payments
- Stripe Connect, RevenueCat for in-app
- Resend
- White-label
- Branding injected server-side per gym. One codebase for every gym's app.
- MCP
- Remote MCP server for Claude, ChatGPT, Gemini and any MCP client
MCP server
Kaizer inside the AI you already use.
Connect it to Claude, ChatGPT, Gemini or any MCP client, and run the gym from a chat.
Claude · sample chatKaizer connectedWho's at risk of leaving this month?
kaizer · members.at_risk({ window: "30d" })3 members, all on Unlimited. Want me to draft a note from their coach?
Kaizer API
Build your own product on Kaizer.
The API behind every Kaizer app, sold on its own. Bring your interface for gyms, coaching or training.
POST /v1/checkins
{ "member": "mem_8f2", "method": "face" }
201 Created
{ "access": "granted", "dues": "paid" }What you can build on the API
- Turnstiles and kiosksCheck-ins straight from the door hardware.
- Corporate wellnessCompanies see visits, employees get perks.
- Physio and rehabPrograms and progress for clinics.
- Wearables and equipmentSend workouts in, pull results out.
- Nutrition appsPlans and meals next to the training.
- Your own member appYour design on top of our data.
Want API or MCP access? Let's talk while I'm in SF.
Book a callAbout
Hi, I'm Octavio.
I co-founded Kaizer and lead its engineering. I've been writing software since 2016, self-taught at first, then a Computer Engineering degree with honors from ITBA in Buenos Aires.
I also teach C programming. Off the clock it's training, movies and planning the next trip.
- Based in
- Buenos Aires
- Coding since
- 2016
- Degree
- ITBA, with honors
- Teaches
- C programming
Kaizer shell 1.0. Type help, or tap a command below.
octavio@kaizer:~$ whoami
Octavio Serpe. Co-founder and CTO at Kaizer.
Buenos Aires, in San Francisco Oct 13–25.
San Francisco · Oct 13–25, 2026
Two weeks in the city. Let's meet.
I'll be around Nob Hill, Pacific Heights, Cow Hollow and the Marina. Happy to come by your gym or studio, or grab a coffee.
10,410 km SFO
37.77°N 122.42°W EZE
34.60°S 58.38°W
San FranciscoPacific time
Buenos Aires+4 hours
Landing Oct 13.
Book a slotTap a day to book it · Pacific time
- Tue Oct 13Land in SF
- Thu Oct 15Vercel ShipPalace of Fine Arts
- Wed Oct 21Resend Forward
- Sun Oct 25Fly back to Buenos Aires
- Every dayGym and studio visits, coffeesPick any open slot
Let's talk
Want to see your gym in Kaizer?
Want to see your coaching business on Kaizer?
Send me your gym's name. I'll set it up in Kaizer with your logo and your classes, and show you how it looks.
Tell me how you coach today. I'll show you how your programs, clients and payments would look in Kaizer.
Emailoctavio@kaizer.app