A complete management system for a gym business, from first enquiry to membership, check-in, payment, trainer payroll and the monthly profit & loss.
Dashboards run on MongoDB aggregation pipelines, so each screen is a single query.
HMAC-signed member QR codes, scanned by camera, with no token storage.
Invoices keep a ledger of payments and refunds; status is derived, never typed.
A scheduler sends expiry, payment and follow-up reminders by email, SMS and WhatsApp.
Revenue from payments minus expenses by category, month by month.
Routes call services, services call repositories behind interfaces, and slow work like sending reminders runs in Celery workers.
Every module follows the same conventions: soft delete, audit log, search, filters and export.
Profiles with health data and BMI, uploads, timeline, soft delete and a field-level audit log.
Plans, renewals, coupons, GST pricing locked at purchase, invoices and payment links.
Manual and QR check-in, late-entry flags, reports and a missed-members list.
Cash, card, UPI and bank transfer with partial payments, refunds and receipts.
Schedules, assigned members, leave approval, salary + commission payroll and performance.
Categorised costs, warranties, maintenance and repairs, barcodes and QR labels.
Sales pipeline with follow-ups, plus templated email, SMS and WhatsApp messages.
Profit & loss with Excel/PDF export, branches, staff roles, audit log, backup and restore.
How the hardest calls were made: what else was on the table, why it lost, and what the chosen design costs.
Plan prices and GST rates change, but past invoices must never change with them.
Pricing is computed once at purchase or renewal and stored with that billing period.
Some data is duplicated across memberships, in exchange for invoices that never drift.
Layered backend (routes → services → repositories behind interfaces) so business logic is unit-tested against in-memory fakes.
Dashboard KPIs, revenue and attendance charts built on MongoDB $facet/$group aggregation pipelines: one round trip per screen.
Member management with soft delete and restore, search/filter/sort, photo and document uploads, a timeline and a field-level audit log.
Memberships with plan freeze/activate, renewals as linked records, coupons, GST pricing snapshotted at purchase, invoices and payment links.
Attendance with manual and HMAC-signed QR check-in by camera, duplicate guards, late-entry flags, reports and a missed-members list.
Payments as an invoice with an embedded transaction ledger: partial payments, refunds, receipts and a derived status.
Trainer HR: schedules, member assignment, attendance, leave approval, salary plus commission payroll and performance snapshots.
Expenses by category with monthly and yearly reports, and CSV, Excel and PDF export from one column definition.
Equipment inventory with warranty, maintenance and repair ledgers, service schedules, barcodes and QR codes.
Lead pipeline with sources, follow-ups, staff assignment and conversion-rate reporting.
Notifications over SMTP email and Twilio SMS/WhatsApp, with templates and a Celery-beat scheduler for expiry, payment and follow-up reminders.
Cross-module reports including a real profit & loss, plus gym settings, branches, staff roles, global audit log and JSON backup/restore.
Production Docker setup: static frontend behind nginx and a hardened, non-root API image.
The code is private, but I'm happy to demo the product and talk through the architecture. I'm available immediately for senior roles and contract work.