QA finding
A page or a single file transfers more data than the budget
QA Warning Severity: Low
Part of the audit Page carbon estimate. Finding id: qa.heavyPagesAndResources.
What it costs you
Every byte is sent on every view. Heavy pages load slowly on mobile connections, use up visitors' data, and account for most of the energy your site uses.
What to do
Start with the files that are both large and used on many pages: resize and compress images, drop scripts and fonts that are not used.
What it checks
- Pages with the largest carbon estimate
- Files with the largest carbon estimate
How to fix it
Cut the transfer size
- Sort the resources of the page by size in the browser's network panel.
- Serve images at the size they are shown and in a compressed format.
- Remove scripts, stylesheets and font files the page does not use.
- Check that text files are sent compressed.
How to check: Reload the page with the cache disabled: the total transferred shown in the network panel is under the budget.
A real case
When YouTube cut its video page from about 1.2 MB to 98 KB, average load time went up, because people in regions where the heavy page took too long to load at all could now watch videos.
Thresholds
| Name | Default | Meaning |
|---|---|---|
max_page_bytes | 3000000 | Budget for the bytes transferred for one page view, HTML plus everything it loads. |
max_resource_bytes | 500000 | Budget for the transfer size of a single file. |