Designing a Real-Time Call Quality Monitoring Platform A ground-up walkthrough of how Zoom, Google Meet, Microsoft Teams, Webex, Slack Huddles, Discord, Amazon Chime and every large VoIP or video platform ingests millions of per-second signals from every endpoint on Earth, turns them into a live picture of “is this call…

Designing a Raise-Hand & Speaker Queue System A ground-up walkthrough of how Zoom, Google Meet, Microsoft Teams, Webex, Clubhouse, Discord Stage, Twitter/X Spaces and every large webinar or town-hall platform lets a hundred thousand participants raise a virtual hand, keeps a fair, ordered queue of who speaks next, promotes them…

Designing a Noise-Cancelling & Background Music System A ground-up walkthrough of how Zoom, Google Meet, Microsoft Teams, Krisp, Discord, WhatsApp calls and every modern voice platform strip a barking dog, a coffee grinder and a wailing siren out of your microphone — and then let you layer soft lo-fi or…

Designing a GPS Spoofing Detection System A ground-up walkthrough of how ride-hailing platforms, food-delivery apps, fleet-tracking backends, drone operators, mobile games and financial-fraud systems detect when a device is lying about where it is — and how to catch a fabricated GPS signal reliably, at planet scale, without blaming the…

Designing DDoS Protection for Signaling Servers in Video Conferencing A ground-up walkthrough of how Zoom, Google Meet, Microsoft Teams, Webex, Jitsi and every large video-conferencing platform keeps its signaling plane — the small, delicate control layer that decides who joins, who leaves, who speaks to whom — alive during volumetric…

Designing a Message Reactions System A ground-up walkthrough of how Slack, iMessage, WhatsApp, Teams, Discord, LinkedIn and every modern messaging or feed platform lets millions of users tap a 👍, ❤️ or a custom emoji on a single message — and how that tiny tap is stored, counted, ordered, fanned…

Designing a Message Forward / Fanout System A complete, ground-up walkthrough of how WhatsApp, Slack, Discord, Twitter/X and every large chat platform take a single message from a single sender and deliver it — reliably, in order and at low latency — to millions of recipients across devices, networks and…

Designing a Language Detection & Routing System for Support Chat A complete, ground-up walkthrough of how modern support platforms — Zendesk, Intercom, Salesforce Service Cloud, WhatsApp Business, and every large in-house chat — detect the customer’s language within a few characters and route the conversation to the right agent, bot…

Designing a Food Delivery ETA Estimation System A complete, ground-up walkthrough of how DoorDash, Uber Eats, Swiggy, Zomato and Deliveroo predict — in real time, for millions of orders a day — exactly when your food will arrive. From the first tap on “Checkout” to the courier ringing your doorbell.…

Designing an Escalation Detection System A complete, ground-up walkthrough of how modern support, trust & safety and incident-response platforms detect — in real time — when a conversation, ticket or alert must be handed off to a human, a senior agent or an on-call responder. From the first signal to…