What is HTL/Sightly?

HTL (HTML Template Language), often referred to as Sightly, is a template system developed by Adobe. It is primarily used for building websites and applications within the Adobe Experience Manager (AEM) platform. HTL emphasizes security and simplicity, automatically providing context-aware escaping to prevent cross-site scripting (XSS) vulnerabilities. It encourages a clear separation of concerns between the template (the visual presentation) and the logic (the data processing), often delegating complex logic to Java backend code or Sling Models. HTL's main goals are to keep markup clean and easily understandable, promote reusability, and increase development efficiency.