Private Chat
Private Chat is a minimal, secure chat application that allows two users to communicate in a short-lived room with realtime updates and automatic destruction.
Tech Stack
The Problem
Most chat applications require persistent accounts and store conversations indefinitely, which is unsuitable for short-lived, private conversations.
1.
No lightweight way to create temporary private chats
2.
Lack of participant limits in shared chat links
3.
Messages persist longer than necessary
4.
Overhead of authentication and user management
The Solution
Private Chat enables ephemeral, secure conversations by enforcing strict room limits, time-based destruction, and realtime synchronization.
1.
Private, shareable chat rooms
2.
Maximum of two participants per room
3.
Self-destructing rooms with TTL countdown
4.
Realtime message synchronization
5.
Manual room destruction with instant client sync
Architecture
A real-time, event-driven chat system built on Next.js with Redis-backed state and pub/sub communication.
1.
Next.js App Router for UI and routing
2.
Elysia-based API mounted under Next.js
3.
Upstash Redis for room metadata and message storage
4.
Upstash Realtime for pub/sub events
5.
Server-side request gate for room access control
Key Technical Decisions
1.
Used Redis with TTL-based keys for room lifecycle management
Enabled automatic room expiration without background cleanup jobs
2.
Restricted rooms to two participants at request-time
Guaranteed privacy and prevented race conditions in room access
3.
Adopted realtime pub/sub instead of WebSocket servers
Simplified infrastructure while retaining realtime behavior
Challenges & Resolutions
1.
Preventing unauthorized access to rooms
Implemented cookie-based auth tokens validated against room metadata
2.
Keeping message history and room TTL in sync
Aligned Redis key expirations on every message write
Future Enhancements
1.
Optional end-to-end encryption
2.
Configurable room TTL
3.
Read receipts and typing indicators
4.
Audit-safe message redaction