Most slow Rails pages are not slow -- a handful of method calls on them are. LazyChain lets you mark those calls in your templates and moves them off the critical path. The page renders right away, and each deferred value loads on its own in a Turbo Frame as soon as it is ready. Values below the fold are never computed at all unless the user scrolls to them. No background job infrastructure, no cache to invalidate by hand, and no JavaScript to write -- just standard Turbo Frames and standard Rails caching.