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The engineering behind everyday internet features.

Interactive deep dives into distributed systems and AI infrastructure. See the architecture, simulate failures, understand the tradeoffs — visually.

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Visual
Interactive diagrams
A
Alice
typing…
Hey! Did you see the match last night?
Yeah it was insane 🔥
That last minute goal though
Under the hood ↓
Phone Gateway Redis
Redis Gateway B Bob
WebSockets · persistent connections Redis Pub/Sub · cross-gateway fan-out TTL expiry · presence as best-effort Consistent hashing · shard by conv_id Reconnect storms · jitter + backoff HLD · LLD · DB Model · Tradeoffs RAG pipelines · coming soon UPI double payment · idempotency keys YouTube live latency · CMAF chunked streaming WebSockets · persistent connections Redis Pub/Sub · cross-gateway fan-out TTL expiry · presence as best-effort Consistent hashing · shard by conv_id Reconnect storms · jitter + backoff HLD · LLD · DB Model · Tradeoffs RAG pipelines · coming soon UPI double payment · idempotency keys YouTube live latency · CMAF chunked streaming
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Live
Episode 03 · Scheduling
Google Calendar Free Slot Detection

How Calendar finds mutual free windows across time zones using 96-bit availability bitmaps, Redis BITOP AND, and 15-min slot granularity.

BitmapsRedis BITOPScheduling
Coming soon
Episode 04 · Streaming
YouTube Live Low Latency

From 30-second satellite delay to sub-3-second streams. CMAF, chunked encoding, CDN edge routing, and ABR algorithms.

CMAFCDNABR
Coming soon
Episode 05 · Realtime Systems
Instagram Seen Receipts

How Instagram delivers read receipts instantly without triggering a DB write per message open. Event batching and cursor mechanics.

Read receiptsRedisEvent sourcing
Coming soon
Episode 06 · Geo / Realtime
Uber Driver Live Tracking

Real-time GPS from driver to rider every second. Location interpolation, geo-indexing, and heading prediction on live maps.

GPSGeo-indexWebSockets
Coming soon
Episode 07 · Notifications
Push Notifications at Scale

APNs, FCM, and the fan-out queue architecture behind 500M device deliveries in seconds. Priority routing and delivery guarantees.

APNsFCMFan-out
Coming soon
Episode 08 · Search
Google Search Autocomplete

How Google serves 6 billion autocomplete queries daily. Trie structures, personalization, real-time trending, and sub-50ms SLA at global scale.

TriePersonalizationCaching
Live now
3 of 40 episodes live · more coming soon
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What you get in every episode
Not just text. An experience.
01 · Architecture
Animated packet flows
Watch events travel across nodes in real time. Click any component to inspect its role.
🗃️
02 · Data Model
Interactive DB schema
Every table, every key. Why it's in Redis and not Postgres. What gets stored vs what expires.
🔍
03 · Design
HLD + LLD walkthrough
High-level system view, then a step-by-step sequence of exact method calls and state transitions.
⚖️
04 · Decisions
Tradeoff radar charts
Every design decision has a cost. Pros, cons, and when the right answer changes.
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Each edition covers one internet feature — with interactive diagrams, full architecture breakdown, and a downloadable PDF.

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