> ## Documentation Index > Fetch the complete documentation index at: https://docs.t3planet.de/en/latest/llms.txt > Use this file to discover all available pages before exploring further. # Content Security Policy (CSP) Requirements To use CKEditor premium features, you must add required CSP rules. CSP means browser security rules for allowed connections and resources. If these rules are missing, premium features may not work. ## Token URL Required to validate your license token with CKEditor cloud services. Without this rule, premium features cannot authenticate. Token URL CSP Connect Src Violation | Violation | URI | Example | | ----------- | --------------------------- | ----------------------- | | connect-src | ORGANIZATION\_ID.cke-cs.com | lb8vps5lhb3m.cke-cs.com | ## Web Socket URI Required for real-time communication. Without this rule, WebSocket connections are blocked. Web Socket URI CSP Connect Src Violation | Violation | URI | Example | | ----------- | ---------------------------------- | ------------------------------ | | connect-src | wss\://ORGANIZATION\_ID.cke-cs.com | wss\://lb8vps5lhb3m.cke-cs.com | ## CKEditor Proxy Allows CKEditor to send specific service events through its secure proxy. This helps premium features communicate reliably. CKEditor Proxy CSP Connect Src Violation | Violation | URI | Example | | ----------- | ------------------------ | ------------------------ | | connect-src | proxy-event.ckeditor.com | proxy-event.ckeditor.com | ## Spell and Grammar Check - Font Source Allows loading required fonts from WebSpellChecker. Without this rule, the spelling tool may not display correctly. Spell and Grammar Check Font Source CSP Violation | Violation | URI | Example | | --------- | ----------------------- | ----------------------- | | font-src | svc.webspellchecker.net | svc.webspellchecker.net | ## Spell and Grammar Check - Image Source Allows loading image files used by the spell-check interface. If blocked, some UI elements may not display. Spell and Grammar Check Image Source CSP Violation | Violation | URI | Example | | --------- | ----------------------- | ----------------------- | | img-src | svc.webspellchecker.net | svc.webspellchecker.net | ## Spell and Grammar Check - Style Source Allows stylesheets from WebSpellChecker. If blocked, spell and grammar UI styles may break. Spell and Grammar Check Style Source CSP Violation | Violation | URI | Example | | -------------- | ----------------------- | ----------------------- | | style-src-elem | svc.webspellchecker.net | svc.webspellchecker.net | ## Spell and Grammar Check Configuration Get your service ID from: [https://webspellchecker.com/wsc-proofreader/](https://webspellchecker.com/wsc-proofreader/) For Source URL, use a CDN or your custom path. Example: [https://svc.webspellchecker.net/spellcheck31/wscbundle/wscbundle.js](https://svc.webspellchecker.net/spellcheck31/wscbundle/wscbundle.js) Spell and Grammar Check Style Source CSP Violation ## Version For CKEditor Pack v44.0.0 and newer, use a valid license key. ## Case: Backend Not Responding The backend may stop responding when CSP is configured incorrectly. More details: [https://forge.typo3.org/issues/106567](https://forge.typo3.org/issues/106567)