Custom Code FAQ

Last Updated: Nov 16, 2018 01:44PM PST

At Classy, we believe in empowering our clients to make the most of our platform. To that end, the Classy platform allows you to add custom code through Custom Content Blocks. In this guide, we will answer some common questions about using custom code on the Classy platform:

Note: Custom code on the Classy Platform is an advanced customization feature that requires coding knowledge. In that sense, the information provided here assumes readers have experience with coding—we do not recommend custom code features for those with no experience. Please note that the Classy Care Team does not provide code development services.   


Does Classy Support Custom Code?

  • Yes, the Classy platform provides custom content blocks for adding HTML and CSS code. These custom blocks are accessible in every Classy campaign type. For information on how to create a custom block, please view our guide

  • Adding code to your campaign is an advanced customization option that does not fall within the scope of support from the Classy Care Team. While we cannot provide code development services, we gathered a few resources that can help at the end of this FAQ.

​What Code Can I Add?

  • Classy supports two types of code—HTML and CSS. We do not accept any other types of code such as JavaScript in order to keep the Classy platform secure for our partners. 

What Can I do With Custom Code?

  • The creative control you gain with custom code depends on your level of expertise. However, common uses include building custom headers, donation buttons, and footers.​ 

  • Example: The Hope Exchange leveraged custom code to create their own spin on impact tiles. Their calculator changes to correlate different gift sizes with impact. 

Hope Exchange's custom impact tiles

What are the Restrictions?


  • Style tags are not supported in the HTML editor. Please use the built-in CSS editor for all styles

  • Script tags or any references to external JavaScript are not supported

  • iFrames are not supported 

  • Insecure URLs are not supported—all URLs must begin with https:// 


  • Classy does not support External Style Sheets. The Classy editor only accepts styles from the built-in CSS editor to maintain a secure platform

  • ​Google Fonts are the only supported external fonts

  • Insecure URLs are not supported—all URLs must begin with https:// 

Block Exclusivity

  • Custom code in the Classy platform only applies to the specific Custom Block it was used to create. That means your HTML and CSS will only apply to the block they were used to create—it is not possible to target elements that live within other content blocks.

  • Block exclusivity prevents any interference with the design of Classy's core template. The core content blocks in Classy campaigns are carefully designed to drive donations, and protecting their code ensures the Classy platform remains secure and effective.

What Are Some Coding Resources?

The Classy Team does not provide code development services, but we recommend a few resources that can help you take advantage of custom code on the Classy platform:

How do I create a Custom Block?

When you are ready to create a custom block, please visit our guide.

Any Final Tips?

  • Once you learn how to create a custom block, feel free to practice coding on the Classy platform. Simply create a mock campaign with a custom block to try out different code combinations. This can help you perfect your skills and gain familiarity with coding on Classy. We recommend naming your mock campaign "Coding Practice” so it is easy to identify and keeping it Unpublished so that supporters cannot access it

  • Eventually, you can use your mock campaign as a source for any custom code you want to reuse in other campaigns. Copy the code of the custom block you want to reuse and paste it into custom blocks in your official campaigns to save time. 

Need any clarifications? Please start a conversation with a member of our Care Team.