Shifter flushes all caches when you publish every new artifacts.
Default cache TTL on Shifter CDN
HTML: 1 hour (60 minutes)
XML RSS Feed: 1 hour (60 minutes)
Application: 1 month (30 days)
JS, CSS, Texts: 1 month (30 days)
Web Fonts: 1 month (30 days)
Images: 1 year (365 days)