Techniques for automatically generating an integrity check hash value for a content asset served by a third-party server when the content asset is added to a template in a user interface. The techniques include displaying, by the user interface, a visual layout of web content, the UI configured to receive modifications to a component of the web content. The component comprising a template for generating hypertext markup language (HTML) embodying the component. The techniques further include receiving a modification to the component of the web content, wherein the modification includes instructions to include a content asset in the component of the web content and detecting that the content asset is hosted on a third-party server. Additionally, the techniques include generating HTML for the web content, the HTML including an integrity hash value for the content asset based on the template.