TITAN GYM · 2026 · FLUTTER WEB, FIREBASE, WHATSAPP & EMAIL AUTOMATION

Titan Gym — Automated Gym Management & Reminders

An automated fitness management platform engineered with Flutter Web and Firebase serverless architecture to eliminate membership expiry revenue leakage and automate customer fee reminders via Email & WhatsApp.

Chapter 02

The Story

Titan Gym grew from a local fitness studio into a premier gym with hundreds of active members. However, as member volume expanded, front-desk operations began experiencing severe friction due to reliance on paper registers, manual spreadsheets, and manual phone call/WhatsApp reminders for fee renewals.

Administrative staff lost track of membership end dates, resulting in members continuing to use gym facilities long after their plans expired without paying. Outstanding balances and partial payment installments recorded in paper notebooks caused accounting discrepancies and uncollected revenue.

To eliminate revenue leakage, streamline member onboarding, and automate fee collection workflows, Titan Gym commissioned the development of the Titan Gym Automated Notification & Management Platform — equipped with automated WhatsApp and Email reminder pipelines.

RoleFull-Stack Developer & System Architect
ClientTitan Gym Fitness Club
ScopeFlutter Web Portal · Firebase Serverless · WhatsApp & Email Automated Reminders · Bulk Excel Import · Operational Dashboard
Year2026
100%Automated WhatsApp & Email Alerts
85%Reduction in Unpaid Dues
95%Faster Member Onboarding
Chapter 03

Connecting client request queues to engineering backlog.

Bulk Data Onboarding

P0 · Critical

Upload legacy Excel member records to onboard 200+ members in under 2 minutes with automated validation.

Dart excel + chunked Firestore batch writes.

Automated Expiry Alerts

P0 · Critical

Multi-stage WhatsApp messages & HTML emails dispatched at T-3 days, T-1 day, and on expiry day to customers & admins.

Node.js 20 Cloud Function Cron + WhatsApp API & Nodemailer.

Partial Payment Ledger

P1 · High Priority

Log installment payments (UPI, Cash, Card), calculate pending balance dues, and maintain audit trails.

Atomic Firestore Transaction updates.

Real-Time Dashboard

P2 · Medium Priority

Live KPI summary cards for Active Members, Expiring Soon, Monthly Revenue, and Pending Balances.

Riverpod reactive Stream Providers.
Chapter 04

How It Was Built (Clean Architecture)

Architectural Blueprint

The application is structured into four decoupled layers: Presentation Layer (Flutter Material 3 UI), State Layer (Riverpod 3.0 reactive providers), Repository Layer (NoSQL data mappings), and Cloud Infrastructure (Firebase Firestore, Node.js 20 Cloud Functions, WhatsApp API & Nodemailer SMTP).

Real-Time Analytics Dashboard

Live metric widgets tracking active members, expiring subscriptions, monthly INR revenue, and outstanding balance dues.

Member Directory & Profiles

Comprehensive directory with status filtering (Active, Expiring Soon, Expired), emergency contacts, and historical payment logs.

Bulk Excel Import Engine

Browser-side binary stream parsing with duplicate phone validation and sub-100 row batch insertion into Cloud Firestore.

Subscription Renewal Engine

Automated plan duration calculation (Days, Months, Years), IST start date alignment, and status lifecycle tracking.

Multi-Mode Payment Recovery

Record Cash, UPI, and Card transactions with auto-calculated balance dues and individual receipt reference numbers.

Automated WhatsApp & Email Reminders

Daily Cloud Function cron (09:00 AM IST) triggering automated WhatsApp messaging and personalized HTML email reminders for members & admins.

Chapter 05

Engineering Challenges & Solutions

1. Timezone Synchronization Across Global Cloud Servers

Challenge: Firebase Cloud Functions run on UTC servers, causing daily cron triggers to evaluate membership expsies at odd hours or miss IST midnight boundaries.
Solution: Enforced explicit Asia/Kolkata timezone calculations in Dart (Intl) and Node.js datetime formatters so daily WhatsApp and Email dispatch jobs execute accurately at 09:00 AM IST.

2. Secure Credentials Isolation for Public Web Clients

Challenge: Storing WhatsApp API keys and SMTP passwords in client-readable Firestore documents exposed messaging credentials to browser network inspection.
Solution: Created private Firestore collections (gym_settings/smtp_secrets) protected by Firestore Security Rules, accessible only via HTTPS Callable Firebase Cloud Functions.

3. High-Volume Bulk Excel Ingestion Without Database Throttling

Challenge: Parsing hundreds of member rows from uploaded Excel sheets threatened to hit Firestore write limits (500/batch) and freeze the web client UI.
Solution: Engineered an async chunked batch service (ExcelImportService) that validates phone numbers, parses streams in web workers, and commits batches under 100 operations.

Chapter 06

The Results

100%Automated WhatsApp & Email Reminders
85%Reduction in Unpaid Dues
2 MinFull Member Base Migration

Titan Gym completely eliminated manual reminder phone calls, automated daily WhatsApp & Email notifications to members and gym admins, recovered uncollected fees, and gained total real-time financial visibility.

← All Work|Titan Gym