Squarespace custom code: five fixes a developer can do in a day

By Axyra Nova Editorial · 9 September 2026 · 5 min read · Website fixes

Squarespace is popular because its templates look good with almost no effort. The catch appears later: a layout that breaks on phones, a section you cannot style the way you want, a button that disappears, or a feature that is almost, but not quite, there. Many owners assume the only answer is a new platform.

Often the answer is a little Squarespace custom code. This guide covers five fixes a developer can usually complete in a day, and how to add code safely so it does not break when the template updates.

Before you add any code

A few ground rules prevent most problems:

  • Check your plan. Some code injection features depend on your Squarespace plan. The Squarespace help centre explains what each plan includes.
  • Use the right place. Site-wide styles belong in the custom CSS panel. Scripts belong in code injection. One-off additions can go in a code block on a page.
  • Comment everything. A short note above each snippet explaining what it does saves time later.
  • Target specific blocks. Use page or section identifiers rather than broad selectors, so a fix for one page does not change every page.
  • Keep a copy of all custom code in a document outside Squarespace.

Fix 1: Mobile layout problems

The most common complaint is a layout that looks fine on a laptop and falls apart on a phone: text overlapping images, columns squashed, buttons pushed off screen.

What a developer does:

  • Identifies the exact sections affected on common phone widths.
  • Adds CSS media queries that adjust spacing, font sizes or stacking order for small screens.
  • Checks that tap targets are large enough and text is readable without zooming.

Mobile visitors are often the majority, so this fix tends to pay for itself quickly. Our mobile-friendly checklist lists what to test.

Over time, pages get renamed or deleted, and links in navigation, buttons and blog posts start leading nowhere.

What a developer does:

  • Crawls the site to find every broken internal and external link.
  • Updates links to their correct destinations.
  • Sets up URL mappings (Squarespace's redirect feature) for pages that moved, so old links still work.

See Broken links: how to find them and why they cost you customers for why this matters.

Fix 3: A sticky call-to-action

Service businesses often want a "Book now" or "Get a quote" button that stays visible as visitors scroll, especially on phones.

What a developer does:

  • Adds a small fixed-position button with CSS, styled to match the brand.
  • Makes sure it does not cover important content or the cookie banner.
  • Hides it on pages where it does not make sense, such as the booking page itself.

Fix 4: Styling a section the editor will not let you change

Templates restrict some styling options: a specific background, a different font size for one heading, a custom hover effect, or spacing that the editor will not allow.

What a developer does:

  • Finds the section's unique identifier.
  • Writes targeted CSS for just that section.
  • Tests the change across screen sizes and in the editor preview.

Fix 5: Small functional additions

Some gaps need a little JavaScript rather than CSS:

  • An announcement bar that shows only during certain dates.
  • A simple FAQ accordion where the template has none.
  • A form tweak, such as hiding a field unless an option is selected.
  • An embedded booking widget from a third-party service.

Keep these minimal. Heavy scripts slow pages down, and anything that depends on a template's internal markup may need adjusting after updates.

Testing after changes

After any custom code:

  1. Check desktop, tablet and phone layouts.
  2. Test in at least two browsers.
  3. Check page speed; Google's Core Web Vitals overview explains which numbers matter.
  4. Make sure the editor still works for whoever updates the site.

When code is not enough

Custom code works well for styling and small features. It is the wrong tool when you need complex booking, memberships, large shops, or full control over hosting and SEO. At that point, a platform change may be worth considering; see Squarespace to WordPress.

How we help

Squarespace fixes are one of our sellers' core services, and our agents flag issues such as missing meta descriptions, broken links and mobile layout problems on Squarespace sites. See the full list on our features page.

A worked example

A yoga studio on Squarespace had three recurring frustrations: the class schedule looked broken on phones, there was no way to keep a "Book a class" button visible, and the instructor bios section could not be styled to match the brand.

A developer addressed all three in an afternoon:

  1. Schedule on mobile. The embedded schedule was wider than the screen. A small CSS rule constrained its width and made it scroll within its own container, so the page no longer scrolled sideways.
  2. Sticky booking button. A fixed-position button was added through code injection, styled with the studio's colours, and hidden on the booking page itself.
  3. Instructor bios. Using the section's identifier, the developer adjusted the image shape, spacing and heading size to match the rest of the site.

Every snippet was commented and saved in a shared document, so the studio could hand it to any developer in future. Nothing required leaving Squarespace.

Keeping custom code maintainable

  • One place per type of change. Keep site-wide CSS in the custom CSS panel, scripts in code injection, and avoid scattering code across many page blocks.
  • Name things clearly. Comments such as "Fix: schedule overflow on mobile (Oct 2026)" make future edits easy.
  • Review after template changes. If you switch templates or Squarespace releases a major update, recheck each customisation.
  • Remove what you no longer need. Old code for past promotions or removed sections adds clutter and can conflict with new changes.

Frequently asked questions

Will custom code break when Squarespace updates?

CSS targeting stable section identifiers usually survives updates. Code that depends on a template's internal structure may need small adjustments. Keeping a documented copy makes fixes quick.

Can I add custom code myself?

Yes, for small CSS changes, if your plan allows it. For anything involving scripts or layout across many pages, a developer saves time and avoids side effects.

Does custom code slow down my site?

Small CSS changes have negligible impact. Large scripts or many third-party embeds can slow pages, so keep additions lean.

How do I find a section's identifier?

Use your browser's developer tools to inspect the section. Squarespace sections and blocks carry identifiers you can target in CSS.