WhatsApp Document Automation System
High-Concurrency Messaging & Bulletin Bot
High-concurrency WhatsApp automation system engineered to generate and distribute personalized PDF bulletins and notifications to 300+ concurrent requests per minute with 99% delivery reliability.
300+ Requests/Min
Concurrency
99% Delivery Rate
Reliability
Zero Crashes
System Load
Executive Overview & Context
A robust messaging engine built for automated PDF document compilation and instant broadcasting. Designed to serve a community of hundreds of concurrent subscribers requesting weekly digital bulletins and schedule notices.
The Problem & Challenge
Sending hundreds of customized weekly PDF documents via WhatsApp manually resulted in account rate limits, thread blocking, server crashes, and missed deliveries.
Engineering Solution & Architecture
Built a queue-backed Node.js microservice utilizing Redis and Bull Queue to decouple incoming WhatsApp triggers from PDF rendering workers. Traffic spikes are smoothed out into controlled rate-limited jobs, guaranteeing 99% delivery.
Key Features Breakdown
Bull Queue Task Rate Limiting
Asynchronous job queue managing document compilation and outgoing socket messages to prevent IP rate limits.
Dynamic PDF Bulletin Synthesizer
Injects database records into clean vector PDF layouts on the fly prior to WhatsApp attachment dispatch.
Subscriber State Machine
MongoDB-backed state tracking managing user subscriptions, preference commands, and delivery confirmation logs.
Technical Architecture
Backend
Queue & Cache
Messaging & PDF
Infrastructure
100% Solo Full-Stack Build
Daniel Kamasi architected, engineered, tested, and deployed this entire software codebase independently from ground zero.