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Squarespace Developer Platform FAQ

This guide covers common questions about The Squarespace Developer Platform, an advanced tool that developers can use to customize their site beyond our built-in custom code tools. The Developer Platform is designed for people with advanced coding knowledge. If you’re already using the Developer Platform, visit our Developer Docs.

The Developer Platform is a premium feature available only in version 7.0 on these plans:
  • Website Business
  • Commerce Basic
  • Commerce Advanced
  • Legacy Website Personal (no longer available)
  • Website Commerce (no longer available)
  • Website Professional (no longer available)

If your site is on version 7.1, you can still add custom code in other ways.

Who is the Developer Platform for?

Most Squarespace users don’t need the Developer Platform because Squarespace provides built-in options like custom HTML, CSS, and Javascript, which allow you to highly customize your site. Some users, like developers and design agencies, require more customization that they can only achieve by writing custom code.

The Developer Platform is only recommended for advanced developers who have experience creating custom websites, and have HTML, LESS CSS, JSON-T, and Git knowledge.

What can I customize with the Developer Platform?

After enabling developer mode, you can:

  • Create a custom 7.0 site template from scratch
  • Modify an existing 7.0 template
  • Access your template's markup, style sheets, scripts, and template design assets

You can’t:

  • Create or modify a custom 7.1 site
  • Access content added via the CMS
  • Add server-side custom code
  • Modify default scripts and styles
  • Modify existing editing tools
  • Customize blocks
  • Customize cover pages

To learn more, visit

How will my site change after enabling developer mode?

If your site still includes demo content, this content will disappear after enabling developer mode. Also:

  • You won't be able to switch templates.
  • Your template won't receive any template updates from Squarespace. Your site will still receive platform-wide updates.

Otherwise, there won’t be any changes to your live site until you update your code.

What happens if I disable developer mode?

If you disable developer mode, you’ll lose some changes that were made while developer mode was enabled. It’s not possible to undo changes or recover all content after you disable developer mode.

When you disable developer mode, you’ll lose:

  • All content in block fields, like sidebars, headers, and footers.
  • Changes to the template, including custom collections, new or modified layouts and regions, new or modified scripts and styles, and uploaded assets and custom types.
  • All of your tweak settings in site styles. These revert to the styles that were in place before you enabled developer mode.
  • The ability to edit existing custom collections. If you try to edit your collections, an error message appears indicating the collections aren’t supported.

Also keep in mind:

  • All custom code in your Custom CSS and Advanced code injection panels remains intact.
  • Content created using standard collections remains intact.

  • Existing content items based on custom post types are still editable as their base content items. It’s not possible to edit your custom fields.
  • The order of your current navigation menu reverts to your site’s original navigation menu order. This includes pages in folders and index pages. Pages from your current navigation menu move to the Not linked section of the Pages panel. You can move pages around your navigation to change this.

What happens if I use developer mode during a trial?

The Developer Platform is a premium feature. During a trial, you have full access to developer mode. Trial sites with developer mode enabled don't expire, giving you as much time as you need to build your custom Squarespace site.

When upgrading to paid service, choose the Website Business plan or higher to continue using developer mode.

If you choose the Personal Plan, we recommend turning developer mode off first. If you leave developer mode on, it stays on and prevents your site from receiving template updates, but you can't make further changes.

What happens if I use developer mode and then downgrade?

If you downgrade to the Personal Plan after activating developer mode:

  • The developer mode customizations you made to your site will remain.
  • Developer mode will stay on, but you won't be able to make any further changes.
  • Because developer mode is still on, you won't receive template updates.
  • To regain access to developer mode, upgrade to the Website Business plan or higher.

Why can't I log in?

If you see an Authentication failed error when you try to log in, it may be because you've enabled two-factor authentication, or that you use social login. In either case, you'll need to create an app password to log in. Alternatively, you can disable two-factor authentication and/or switch your login method to email and password.

Can I contact Customer Support for help?

You can contact us with questions about enabling and getting started with the Squarespace Developer Platform. We can't help you write or troubleshoot custom code solutions, however, as these topics fall outside our scope of our support. For this reason, we only recommend the Developer Platform if you have advanced knowledge of coding languages and can troubleshoot code issues independently.

If you have questions about custom code, try these resources:

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