IconVault's Periodic Background Sync Playground teaches the PeriodicSync API by letting you touch it. It runs a live capability check on your browser (service worker support, periodicSync manager, secure context, and the periodic-background-sync permission), reads the tags genuinely registered on your origin, and lets you register a real tag with a configurable minimum interval. A compressed timeline simulation then shows the rhythm of periodicsync events firing. It is free and runs fully in your browser.

Periodic background sync is how installed PWAs refresh content while closed, but it is gated by engagement, installation, and browser heuristics, which makes it hard to learn from docs alone. This lab separates what is real (detection, registration, tag listing) from what is simulated (the compressed timeline) so you understand the actual API contract, including the crucial detail that the browser guarantees 'at least this often', never exact timing.