Dev Tools · 1h ago
Preload hint slashes Blazor WASM LCP by 500ms
A developer cut Largest Contentful Paint (LCP) on a Blazor WebAssembly site from 3.5s to under 2s by adding a single <link rel=preload> tag. The fix addressed a 5.5-second "element render delay" caused by a small JSON file being fetched after all .wasm assemblies loaded. The technique is applicable to any Blazor WASM app where initial data fetches block rendering.
Meridian48 take
A simple preload hint can dramatically improve perceived performance, but the deeper issue is Blazor's boot sequence forcing data fetches to wait until the entire runtime loads.
Read the full reporting
One <link rel=preload> cut my Blazor WASM LCP by 500ms — the invisible file at the end of the critical chain →
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blazorweb-performance