CASE STUDY
Prep Doctors
Three production-grade enterprise applications. 425,000+ lines of code. One developer. Six months.
Prep Doctors is a dental exam preparation company operating across Canada, the United States, and Australia. They needed a unified software platform to manage their operations — from student enrollment and payment collection to session scheduling, staff coordination, and regulatory compliance.
Between June 2025 and January 2026, we designed and built their entire digital operations platform as a solo developer: a payment processing system, an internal operations dashboard, and a public-facing marketing website. All three applications are production-grade, fully deployed, and interconnected — forming a single coherent system that covers the full lifecycle of the business.
The platform at a glance
Checkout
Payment processing & invoicing
- 73,000+ LOC
- 45+ API endpoints
- Multi-country Stripe
PrepOne
Internal operations dashboard
- 306,000+ LOC
- 388 API routes
- 87 DB tables
- 40+ sections
Website
Public marketing & enrollment
- 46,000+ LOC
- 47 pages
- 6 enrollment flows
425,000+ total lines of code · 430+ API endpoints · 87 database tables
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Checkout — Payment Processing Platform
checkout.prepdoctors.com · Express.js, Node.js, Stripe, Vercel Serverless
Multi-Country Stripe Integration
Separate Stripe organizations for Canadian (CAD) and Australian (AUD) operations, automatically routing transactions based on program and region.
Payment Links & Installment Plans
Staff generate branded payment pages with program-specific pricing and payment plan options. Automated daily processing with exponential backoff on failures.
Discount & Pricing Engine
Full discount code system with validation rules, usage tracking, multiple discount types, early bird pricing, and automatic provincial tax computation.
Electronic Signatures
Built-in enrollment agreement and NDA signing with Redis-cached agreement rendering. No third-party e-signature tool required.
Circuit Breaker Pattern
External API calls wrapped in circuit breakers with configurable failure thresholds, half-open testing, and automatic recovery for graceful degradation.
PCI-Compliant Audit Logging
Every transaction generates a compliance event with automatic sensitive data redaction. Redis deduplication prevents double-charges. Feature flags enable canary deployments.
PrepOne — Operations Dashboard
dashboard.prepdoctors.com · Next.js 15, React 19, TypeScript, Drizzle ORM, Neon PostgreSQL
Financial Intelligence
Executive summary, revenue analytics, accounts receivable, cash flow projections, deposit tracking, and full transaction history — all filterable by date, program, campus, and cohort.
Payment Operations Center
Real-time unified timeline, manual charge processing, retry management, anomaly detection with severity classification, payment funnel tracking, and failure analysis.
Cohort Command Center
Master-detail layout with filterable cohort list and six-tab detail panel. URL-driven state for deep-linkable views. Real-time seat counts and bulk operations.
Calendar System (28K+ LOC)
Five view modes with drag-and-drop, 35+ components, conflict detection wizard, venue utilization, instructor load balancing, edit request workflows, and multi-campus support.
AI Email Builder & Communications
Visual email editor with AI-generated HTML, embedded chat assistant, SMS via Twilio, delivery tracking, Microsoft Teams integration, and centralized notification routing.
CRM & Student Management
Unified student profiles, deal pipeline, activity timeline, HubSpot bidirectional sync with 60+ webhooks, dedicated Sync Command Center, and data quality monitoring.
QR Attendance System
Camera-based QR scanner with USB barcode fallback, student portal with OTP auth, staff PWA with offline queue, and floating decision panel for mode mismatches.
T2202 Tax Certificates
Automated Canadian tuition tax certificate calculation, generation, and distribution — replacing manual spreadsheet work.
Advisory Booking
Five-factor advisor matching algorithm, 0-100 lead scoring, and real-time walk-in queue management across physical campuses.
Access Control
Microsoft Entra ID SSO with database-backed sessions, full RBAC with PagePermissionGate on every page, role hierarchy with user-level overrides, and Cmd+K command palette.
Website — Marketing & Enrollment
one-prep-website.vercel.app · Next.js 15 (PPR), React 19, TypeScript, Tailwind CSS 4
Six Enrollment Flows
Program-specific enrollment forms built on a shared base component with Zod validation, registration record creation, and Checkout payment redirect.
First-Party Analytics
Custom analytics tracking page views, events, and conversions with geo-IP enrichment. No Google Analytics dependency — the business owns its data.
PIPEDA Compliance
Granular cookie consent banner, preference management modal, consent audit trail, and Google Tag Manager that only loads after explicit consent.
Performance & Quality
Next.js 15 PPR for optimal TTFB, 250 tests (38 E2E + 212 unit), AVIF-first images, 62 SEO redirect rules, and full security headers.
How everything connects
The three applications form an integrated platform where a student's journey flows seamlessly across all three.
Student discovers a program on the Website and submits an enrollment form.
The Website creates a registration record and generates a Checkout payment link.
Checkout presents payment options, processes the charge through Stripe, and confirms.
Payment confirmation flows back to PrepOne — the student appears in the CRM, cohort enrollment is recorded, and a welcome email is sent.
Staff manage everything through PrepOne: attendance, communications, payments, tax certificates, advisory bookings.
Technical foundation
Authentication
Microsoft Entra ID SSO, database-backed sessions, domain-restricted access
Authorization
Full RBAC with permission gates on every page, role hierarchy, user-level overrides
Payment Processing
Multi-org Stripe (Canada + Australia), automated scheduling, circuit breaker, retry with backoff
Data Integrity
Redis deduplication, PCI-compliant audit logging, sensitive data redaction
Database
87 PostgreSQL tables via Drizzle ORM, shared across all applications
Communications
Centralized email (Resend) + SMS (Twilio), AI-powered content generation, delivery tracking
API Surface
430+ API endpoints across three applications
Automation
10+ cron jobs: payment processing, data quality, sync, reminders, reconciliation
Testing
30 test specs (Checkout), 38 E2E + 212 unit tests (Website)
Compliance
PIPEDA privacy controls, PCI DSS audit logging, consent management with audit trail
Performance
Next.js 15 PPR, AVIF/WebP images, server-side rendering
Monitoring
Sentry across client/server/edge, structured logging, health checks, anomaly detection
Technology stack
Built solo in six months
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