The Desi Architect
Notes / Design Interview Problems / Design Notification System (Push, SMS, Email at Scale)
Track 5 · Design Interview Problems

Design Notification System (Push, SMS, Email at Scale)

Order updates, OTPs, a Diwali sale blast to one crore phones, all through the same pipe. The hard part is not sending. It is making sure the OTP never waits behind the sale and nobody gets the same SMS twice.

Interview problem22 min read1 interactive
On this page
  1. The 07:45 PM Diwali blast and the missing OTP
  2. 🟢 Layer 1: Core Mechanics & The Priority Lanes
  3. 🟡 Layer 2: Provider Throttling, Fallbacks & Sizing
  4. 🔴 Layer 3: Architect's Corner