Cache Invalidation & Purging Strategies
Master the techniques for removing or refreshing stale cached content: purge by URL, by tag, soft vs hard purge, and the tradeoffs of each.
Why Invalidation Is Hard
There is a famous saying that one of the two hard things in computing is cache invalidation. The challenge is removing stale content everywhere it lives without harming performance.
- Content is replicated across many edge locations
- Removing too aggressively kills your hit ratio
- Removing too little serves stale data
Purge by Single URL
The simplest purge targets one exact URL. Fast and precise, but tedious when many related objects change at once.
curl -X POST "https://api.cdn.com/purge" -d "url=/images/logo.png"All lessons in this course
- Cache Busting & Versioning
- Monitoring Cache Hit Ratios
- Troubleshooting Cache Issues
- Cache Invalidation & Purging Strategies