Find information about the Square Snippets and Sites APIs that you can use to add custom functionality to Square Online sites.
Square Online

Build eCommerce Applications for Square Online

Square Online provides all the tools that Square sellers need to quickly build eCommerce websites and start selling online for free. As a developer, you can use the Snippets and Sites APIs to create new integrations and third-party applications that extend Square Online features to help meet the many needs of Square sellers.


If you are looking for information about website payment processing options for the Square developer platform, see Online Payment Options.

The Snippets API lets you insert snippets that provide custom functionality into Square Online sites. A snippet is a script that is injected into the <head> element of all pages on a site, except for checkout pages.

  1. Sign up for a Square developer account and create your first Square application.

  2. Create a free Square Online site.

  3. Sign in to API Explorer and try out the Snippets and Sites APIs.

  4. Build and test your snippet code.

  5. Use the Snippets API to insert the snippet into your site, and then test it on your site.

  6. Apply to become an App Partner and list your application in the Square App Marketplace.

The Sites API provides the ListSites endpoint used to retrieve metadata about the Square Online sites that belong to a Square seller.


Developers can also write embeddable code that Square sellers can add directly to their sites. For more information, see Add External Content and Widgets with Embedded Code in Square Online.

The Sites API and Snippets API are publicly available to all developers as part of an early access program (EAP). These APIs can be used to build production-ready applications for Square Online. During the EAP, Square might contact developers who are using these APIs to gather feedback that can help improve the developer experience.

Square does not provide a sandbox eCommerce environment for testing calls to Square Online APIs. For information about testing in the production environment, see Test your application.

If you need more assistance, contact Developer Support or ask for help in the Developer Forums.