Squarespace
Content renders server-side, which is the important part, but head-level control is limited to what the injection panel allows.
What tends to go wrong here
Squarespace handles the basics ... titles, descriptions, canonical, sitemap, Open Graph ... without configuration. Where it gets awkward is anything requiring precise control over the document head or the heading levels a section component produces.
Where the findings land
- Easy To Fix
- Titles, descriptions, images and alt text, page-level Open Graph. All in the editor.
- Harder To Fix
- Custom structured data, which goes through code injection and applies broadly rather than per page. Heading levels, which section components choose for you.
- Usually Structural
- Nothing about rendering. The constraint is the ceiling on markup control, not the delivery model.
Worth knowing
The recurring Squarespace finding is multiple H1s, because several section types render their title as an H1 by default. It is fixable with a small amount of CSS-aware restructuring, and not always fixable per page.
Others in Site Builders
Find out which of these apply to you
Everything above is what usually happens on this platform. The inspection tells you what is actually happening on your page.