Can a club CRM work with the booking and payment software the clubs already use?

Yes. It integrates with those systems (bookings, payments) instead of replacing them, and data and permissions are scoped per club.

What can WhatsApp campaigns do in a club CRM?

Send messages for different events to clients and to trainers, with personalised messages and links. Funnels send a series of messages to bring clients back. There are birthday greetings and a back-to-school greeting for clients who listed children. Campaigns are protected against duplicate sends.

How are mailings and advertising campaigns tracked?

Mailings are tracked through the system’s own redirect, and advertising campaigns get their own tracking links.

Is trainer payroll calculated automatically?

Yes. Trainer pay is calculated automatically by complex formulas, and the trainer report is built from confirmed sessions (group, personal, rental).

Which reports does it give?

Reports by visitor segment: how steady the client base is, growth, churn, advertising effectiveness, and trainer performance in personal and group sessions. Financial reports are built in different cuts from the card-payment terminal service, plus a P&L from payment data and manual expenses.

Can clients book personal sessions online?

Yes. The club website shows the schedule and visitors book personal sessions themselves. The client and the trainer both get a WhatsApp notification.

CRM for a network of martial-arts clubs

A network of clubs now brings clients back with WhatsApp funnels, sees which advertising and which trainers pay off, pays trainers automatically and takes personal-session bookings from its website. I built it as a layer on top of the software the clubs already used.

§01 The case in detail

Task: A network of clubs needed to bring clients back, see what advertising and each trainer actually bring, and pay trainers correctly, without replacing the booking and payment software it already used.
What it does for the business: WhatsApp messages for different events, to clients and to trainers. Setup is flexible: links, and personalised messages with links.
Own tracking of mailings through a redirect, and own tracking links for advertising campaigns.
Funnels of messages: a series that brings clients back to the club.
Personal touches: birthday greetings, and a back-to-school greeting for clients who listed children in their profile.
Many reports by visitor segment: how steady the client base is, growth, churn, advertising effectiveness, trainer performance in personal and group sessions.
A card-payment terminal service is connected, and financial reports are built in different cuts.
Trainer pay is calculated automatically by complex formulas.
The club website shows the schedule, and visitors book personal sessions themselves; the client and the trainer both get a WhatsApp notification.
One system for several clubs, multi-club and multi-country.
Under the hood: Integrations with the systems the clubs already used (bookings, payments)
WhatsApp campaigns protected against duplicate sends (a unique key: client / club / scenario / step)
Trainer availability windows for personal sessions
Trainer report calculated from confirmed sessions (group, personal, rental)
P&L from payment data and manual expenses by category
A public API for the website with scoped keys
Constraint: It lives inside systems I do not own, so data and permissions are scoped per club.
Stack: FastAPI · Jinja + HTMX · PostgreSQL 16 · ~25 scheduled jobs in the app · queue = a Postgres table · no Redis
Result: Mailings, reports, trainer pay and online booking of personal sessions run in one system on top of the software the clubs already used. The P&L report is assembled automatically, and reception no longer agrees personal-session times by hand.

Engineering behind it *■ confirmed*
Commits	3,847
Days with commits	172
First commit	23.03.2026
Python in app/	~76,800 lines
Templates	17,600 lines
Server tests	6,812
e2e tests	816
Security commits	37
Reviews	red/blue team reports

Architecture

Architecture as text: who passes what to whom

Bookings

Booking system → CRM API: webhook
Booking system → Scheduler: poll, sync
CRM API → PostgreSQL: events, visits

Terminal payments

Payments system → Scheduler: terminal payments
Scheduler → PostgreSQL: payments, payroll
Staff UI ↔ CRM API: segment reports

WhatsApp and tracking

Scheduler → Outbox: queue: events, funnels, birthdays
Outbox → Meta WhatsApp: template, text
Meta WhatsApp → CRM API: statuses, inbound
CRM API → Telegram: inbound alert
Telegram bot ↔ Telegram: approval card, tap
CRM API ↔ LLM: text, chat
Meta WhatsApp → Scheduler: cost analytics

Website booking

Club website ↔ CRM API: schedule, bookings
CRM API → Meta WhatsApp: login code, booking notices
CRM API → Booking system: create, cancel

Backup

Scheduler → Telegram: encrypted dump

§02 CRM for martial arts clubs: problem, approach, outcome

Problem: A network of clubs needed to bring clients back, see what advertising and each trainer actually bring, and pay trainers correctly, without replacing its booking and payment software.
Approach: A CRM layer on top of the existing software: integrations with the booking and payment systems, WhatsApp campaigns with funnels and tracked links, reports by visitor segment, automatic trainer pay, and a website integration where visitors book personal sessions.
Outcome: Mailings, reports, trainer pay and online booking of personal sessions run in one system. The P&L report is assembled automatically, and reception no longer agrees personal-session times by hand.

Short answers

Can a club CRM work with the booking and payment software the clubs already use?: Yes. It integrates with those systems (bookings, payments) instead of replacing them, and data and permissions are scoped per club.
What can WhatsApp campaigns do in a club CRM?: Send messages for different events to clients and to trainers, with personalised messages and links. Funnels send a series of messages to bring clients back. There are birthday greetings and a back-to-school greeting for clients who listed children. Campaigns are protected against duplicate sends.
How are mailings and advertising campaigns tracked?: Mailings are tracked through the system’s own redirect, and advertising campaigns get their own tracking links.
Is trainer payroll calculated automatically?: Yes. Trainer pay is calculated automatically by complex formulas, and the trainer report is built from confirmed sessions (group, personal, rental).
Which reports does it give?: Reports by visitor segment: how steady the client base is, growth, churn, advertising effectiveness, and trainer performance in personal and group sessions. Financial reports are built in different cuts from the card-payment terminal service, plus a P&L from payment data and manual expenses.
Can clients book personal sessions online?: Yes. The club website shows the schedule and visitors book personal sessions themselves. The client and the trainer both get a WhatsApp notification.

§03 Related

Approval system for financial requestsPersonal project: rules as data, encryption, audit log
Team forecasting systemDeterministic Monte Carlo, no LLM on the numbers
Person dossier aggregator from official sourcesMany sources, one reviewed dossier
LLM integration into working systemsWire a model into the POS, booking, CRM, messengers

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