StayDue
A SaaS that automatically reminds university students of upcoming deadlines by syncing their Moodle calendar. Delivers reminders via WhatsApp and email through a pipeline that runs three times daily, with automatic rollback if a message fails.
Impact & Key Metrics
Technology Stack & Skills
Project Overview & Scope
StayDue is a production SaaS application designed to solve deadline tracking challenges for university students by automatically synchronizing their Moodle academic calendars. By integrating directly with Moodle calendar feeds, StayDue eliminates manual schedule management and keeps students informed of critical assignment deadlines and exam schedules.
The platform delivers automated notifications via WhatsApp and email through a scheduled pipeline that runs three times daily. Designed with built-in failure recovery, the delivery engine features automatic transaction rollback if a notification fails, ensuring data consistency and delivery tracking.
Behind the student-facing notification system, StayDue includes a complete administration panel that provides operational monitoring for revenue tracking, user subscriptions, trial enforcement, and overall system health.
System Architecture & Data Flow
StayDue processes academic deadline notifications through a scheduled end-to-end data pipeline: Moodle Calendar Feed → Application Engine & Database → Scheduled Reminder Pipeline (3x Daily) → Multi-Channel Delivery (WhatsApp / Email) → Success/Failure Tracking & Automatic Rollback
Key Technical Decisions
Multi-Channel Messaging Infrastructure
Context: University students require immediate notification on daily messaging channels alongside standard email.
Decision: Selected Meta WhatsApp Business API alongside Resend email integration for dual-channel notification delivery.
- Direct delivery to WhatsApp with verified delivery tracking
- Reliable email fallback for all scheduled deadline reminders
Three-Times-Daily Scheduled Pipeline
Context: Moodle calendar feeds must be regularly checked and upcoming deadlines dispatched throughout the day.
Decision: Automated a background execution engine running three times daily via Vercel Cron.
- Timely deadline reminders without continuous polling overhead
- Consistent batch processing of student notification queues
NextAuth.js & MongoDB Data Layer
Context: Session management and user persistence needed to support per-user subscription and trial state.
Decision: Paired NextAuth.js session handling with MongoDB persistence for user preferences and notification logs.
- Secure authentication for student accounts and admin dashboard
- Scalable storage for subscription states and delivery metrics
Technical Challenges & Solutions
Reliable Message Delivery & Failure Rollback
Problem: External messaging service failures or network glitches could lead to inconsistent notification status if a dispatch attempt failed midway.
Solution: Engineered an automatic transaction rollback mechanism that captures delivery status and reverts incomplete notification states upon message failure.
Impact: Guaranteed accurate delivery tracking and prevented duplicate or dropped notifications.
Meta WhatsApp Webhook Security & Trial Enforcement
Problem: Securing inbound webhook events from Meta while enforcing per-user trial limitations and subscription boundaries.
Solution: Implemented webhook signature verification alongside automated trial status checks before dispatching notification payloads.
Impact: Protected delivery endpoints against unauthorized access and enforced tier enforcement.
Key Outcomes & Verification
- Launched and deployed StayDue as a live production SaaS for university students.
- Achieved 83% onboarding conversion rate across initial registered users.
- Dispatched over 132 automated deadline notifications via WhatsApp and email channels.
- Built full administrative tooling for tracking revenue, subscriptions, trial enforcement, and system health.