Technical Case Study: Engineering Jaaiye - High - Concurrency Social Planning API

Introduction

Jaaiye is an all -in -one social scheduling application designed for group coordination, hangout planning, and shared expense management.As the Lead Backend Developer, I architected a high - concurrency API infrastructure to handle real - time synchronization across thousands of users and multiple external platforms.

The Problem: Coordination Chaos & Calendar Drift

The core challenge in social planning is "data drift." When a group tries to coordinate across different time zones, personal calendars, and messaging apps, information becomes fragmented:

** Calendar Fragmentation:** Users rely on diverse providers(Google, Apple, Outlook), making it hard to find common availability.
** Real - Time Updates:** Change in location or time must propagate instantly to all participants to avoid missed events.
** Expense Accountability:** Tracking and splitting group contributions in real - time requires strict transactional integrity.

Solution Architecture: Modular Node.js & Real - Time Sync

I built a scalable RESTful API with a focus on modularity and event - driven communication.

The Stack:

** Backend:** Node.js & Express(TypeScript) for a performant, non - blocking API.
** Database:** MongoDB for flexible event schemas and geo - spatial queries.
** Real - Time:** WebSockets(Socket.io) for instant event updates.
** Caching:** Redis for session management and rate limiting.
** Integrations:** Google Calendar API, Payment Gateways.

Overcoming Key Challenges

Challenge 1: Bidirectional Google Calendar Sync

Synchronizing internal event states with external Google Calendars while avoiding infinite update loops.

** Problem:** Every change in Jaaiye needs to hit Google Calendar, and every external change needs to reflect in Jaaiye.
** Solution:** Implemented a robust OAuth2 flow combined with a Webhook listener.I developed a "Source of Truth" reconciliation algorithm that uses unique ETag identifiers to determine which platform has the latest data, effectively preventing race conditions and redundant API calls.

Challenge 2: Real - Time Coordination with WebSockets

Ensuring all participants see real - time changes(location, member status, expense splits).

** Problem:** Traditional polling would create immense load and lag.
** Solution:** Leveraged Socket.io to establish persistent connections.When an event is updated, a specific "room" payload is broadcast to all active group members, ensuring sub - second updates for critical data like location changes or bill splits.

Challenge 3: Transactional Expense Splitting in NoSQL

Managing financial splits in MongoDB, which traditionally lacks the ACID guarantees of relational databases.

** Problem:** A partial failure during an expense split could result in "missing money" or ghost debts.
** Solution:** Utilized MongoDB Multi - Document Transactions(Sessions).This ensures that the update for the main "Wallet," the creation of the "Transaction Record," and the update of individual "User Debts" are processed atomically — either all succeed or none do.

Results & Impact

* ** Seamless Integration:** Successfully synchronized events across 1000 + active user calendars.

** Performance:** Achieved sub - 500ms response times for complex group queries through Redis caching.
** Scalability:** The modular architecture allows for the rapid addition of new modules(like "Nearby Hangouts") without affecting core performance.

Conclusion

Jaaiye demonstrates how a modern Node.js stack can solve complex synchronization problems.By combining NoSQL flexibility with strict transactional logic, I built a platform that brings order to social chaos.

[Visit Jaaiye](https://jaaiye.com) | [App Store](https://apps.apple.com/us/app/jaaiye/id6445222114);

Technical Case Study: Jaaiye