Skip to main content
Checks for render-blocking CSS and JavaScript
Rule IDperf/render-blocking
CategoryPerformance
ScopePer-page
Severitywarning
Weight6/10

​
Solution

Render-blocking resources delay First Contentful Paint (FCP) and LCP. Fix by: 1) Inline critical CSS for above-fold content. 2) Load non-critical CSS with media=‘print’ onload=‘this.media=all’. 3) Add async or defer to non-critical scripts. 4) Move scripts to end of body when possible. 5) Use <link rel='preload'> for critical resources. Consider tools like Critical to extract critical CSS.

​
Enable / Disable

​
Disable this rule

squirrel.toml
[rules]
disable = ["perf/render-blocking"]

​
Disable all Performance rules

squirrel.toml
[rules]
disable = ["perf/*"]

​
Enable only this rule

squirrel.toml
[rules]
enable = ["perf/render-blocking"]
disable = ["*"]