How Meta optimizes Facebook for iOS start time
Original post Optimizing Facebook for iOS start time
Article Summary
Natansh Verma from Facebook reveals how their team shaved multiple seconds off iOS app launch time. The biggest surprise? Network wasn't the bottleneck they expected.
Facebook's iOS team tackled one of mobile's most critical metrics: cold start time. They broke down the launch sequence into three phases (request, network, response) and discovered their assumptions about performance bottlenecks were completely wrong. This led to creative solutions that fundamentally changed how they approached the problem.
Key Takeaways
- Cold start spent ~1 second on initialization before feed request even left the device
- UDP Priming sends encrypted packets before TCP to pre-cache server data
- Moving from 3+7 to 1+1+X story fetching cut hundreds of milliseconds
- Deferring non-critical services until after launch reduced resource contention
By challenging assumptions and reducing feed request dependencies, Facebook achieved multi-second improvements in iOS cold start performance.
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This page summarizes “Optimizing Facebook for iOS start time” by Meta, published Nov 20, 2015. All credit for the original work goes to the authors.
