The Theme JavaScript That Blocked Rendering for 1.2 Seconds
One script tag without defer, loading a bundle nothing above the fold needed. How to find what is blocking your paint and what each fix actually changes.
| Change | FCP | LCP |
|---|---|---|
| Baseline | 2,410 ms | 3,890 ms |
defer on theme bundle |
1,290 ms | 2,740 ms |
| Section code split out | 1,180 ms | 2,210 ms |
| Preconnect to app origins | 1,140 ms | 2,050 ms |
| Hero image priority fixed | 1,140 ms | 1,320 ms |
Related reading: Tapping a Variant Took 480ms to Do Anything explores a connected angle.
Published on debugly.dev by Rohit Bhadani | Founder of Krova Cloud
