Introducing Twitter Image Pipeline iOS Framework For Open Source

Twitter open sourced their iOS image pipeline after hitting a breaking point: 2GB caches, corrupted images, and no way to clear data when users logged out. Here's how they rebuilt it from scratch.

In 2017, Twitter's engineering team released TIP (Twitter Image Pipeline), their battle-tested iOS framework for image loading and caching. After two years of internal iteration solving critical performance and reliability issues, they made it available to the broader iOS community.

Key Takeaways

• Reduced cache size from 2GB+ to 128MB using LRU purging and configurable limits
• Three-tier caching system: rendered in-memory, raw in-memory, and persistent on-disk
• Progressive JPEG support delivers content faster on slow connections worldwide
• Automatic request coalescing and download resuming minimize wasted network calls
• Pluggable codec architecture supports JPEG, PNG, GIF, WebP, and custom formats

The framework includes built-in debugging tools that let developers inspect cached images at runtime, a feature Twitter's own engineers use daily.