Journal
Engineering
Delivering Daily Cards to Thousands, Reliably
The engineering behind sending scheduled WhatsApp cards without dropping a single subscriber.
TThe SRAAT Team 7 min read
Sending one message is easy. Sending a hundred thousand personalized, timezone-aware, rate-limited messages across a rolling 24-hour window is a different problem entirely.
Batching by timezone
SRAAT rolls delivery windows around the world, respecting each subscriber's Fajr — or their preferred time — while staying inside carrier rate limits.
Retries and receipts
Every delivery is tracked. Failed sends are retried with exponential backoff. Read receipts feed analytics, not surveillance.