📝 System Design Interview Classics
System Design Interview Classics architecture diagram templates
URL shortener, chat, news feed, ride matching, rate limiter and other interview favourites. Open any template to see the finished diagram, then use it as the starting point for your own in the Studio.
11 templates
URL Shortener System Design
The classic interview design for a service like bit.ly: short code generation, fast redirects from a cache, and click analytics processed separately.
Chat App Message Delivery (WhatsApp-style)
How a one-to-one chat message is delivered in a WhatsApp-style system, with sent, delivered and read ticks, and push notifications when the receiver is offline.
Social News Feed (Twitter-style)
How posts reach followers' feeds: fan-out on write for normal users, fan-out on read for celebrities, and a ranked feed built from a cache.
Ride Matching System (Uber-style)
The core of a ride-hailing app: drivers stream their locations, a geo index finds nearby drivers, and a matching service offers the trip to the best one.
API Rate Limiter (Token Bucket)
How a token bucket rate limiter decides whether to let an API request through, using Redis so all servers share the same counts.
Notification Service Design
A notification system that sends email, SMS and push messages at scale: one API, a queue per channel, user preferences, and retries.
Search Autocomplete (Typeahead)
How search suggestions appear as you type: a prefix index built offline from past searches, served from memory, and refreshed regularly.
Movie Ticket Booking (BookMyShow-style)
How seat booking avoids double-selling: seats are locked for a few minutes during payment, and released if payment fails or times out.
Video Upload and Streaming (YouTube-style)
How uploaded videos become streamable: resumable upload, transcoding into several qualities, storage, and delivery through a CDN with adaptive bitrate.
Distributed Cache with Consistent Hashing
How a distributed cache spreads keys across nodes with consistent hashing, so adding or removing a node moves only a small share of keys.
File Sync States (Dropbox-style)
The states a file goes through in a sync client like Dropbox: detected, chunked, uploaded, synced, and conflict handling when two devices edit the same file.
More System Design Interview Classics templates are being added regularly.