How Bitly Works: Scalable URL Shortener Design
Ever wondered how services like Bitly turn huge URLs into tiny, reliable links—handling billions of hits a day? In this video, we'll break down the system design of a scalable URL shortener, covering everything from unique code generation to database sharding and caching tricks. Get ready to see how big links become small keys.
Chapters:
0:00:00 Intro
0:00:03 Why Shorten URLs?
0:00:27 Let's Set Requirements
0:00:48 A Bird's-Eye View: High-Level Architecture
0:01:07 Naive Approach: Just Use a Hash
0:01:31 Better: Incrementing IDs and Base62
0:01:50 How Many Links? Base62 Math
0:02:05 Under the Hood: URL Mapping Table
0:02:17 API Contract: Shorten and Resolve
0:02:29 The Write Path: Creating a Short Link
0:02:44 The Read Path: Resolving Short Links
0:03:01 Why Cache Matters
0:03:17 But Wait: No Two Links Alike
0:03:35 Scaling the Backend: Sharding
0:03:49 When Things Go Wrong: Hot Keys & Lost Links
0:04:08 Monolith vs Scalable Design
0:04:22 The Takeaway
#urlshortener #bitly #systemdesign #scalability #database