SDK caching principles

How the SDK caches content. You can control the cache size sings controls described here.

Principles

App size vs cache

Caching doesn't meaningfully change the app’s download or install size. It does increase on-device storage usage at runtime. In this regard, consider as follow

Where cached data lives

Cached media is stored in OS cache locations (cache or temporary directories). The OS can purge it under storage pressure, and the SDK will refill it as needed.

Purpose of caching

Caching reduces loading time by keeping the next likely assets available, including thumbnails, upcoming pages or items, and video startup bytes.

Default behavior

Prefetch level
The SDK uses the default prefetch policy.
Cache size
The SDK uses a platform default cache budget if cachingSize is nil. This is typically about 500Mb.
Runtime behavior
The SDK automatically prefetches and caches around viewer navigation and playback to improve perceived performance.

What gets prefetched

Prepared content (optional warm-up)
Content lists for faster entry.
Images
Thumbnail and poster URLs.
Stories
Upcoming pages.
Moments and Videos
Upcoming items. For Videos, startup bytes are prefetched to improve time to first frame. The SDK doesn't cache the entire video; instead, it caches a small segment to allow immediate playback.

How to adjust caching

You can adjust the cache by making the calls to the SDK:

Cache size (MB) — cachingSize