Attention

TYPO3 v12 has reached end-of-life as of April 30th 2026 and is no longer being maintained. Use the version switcher on the top left of this page to select documentation for a supported version of TYPO3.

Need more time before upgrading? You can purchase Extended Long Term Support (ELTS) for TYPO3 v12 here: TYPO3 ELTS.

YAML

YAML is used in TYPO3 for various configurations; most notable are

Event listeners in Configuration/Services.yaml
Dependency injection information in Configuration/Services.yaml
Site configuration in sites/<identifier>/config.yaml
System extension form configuration
System extension rte_ckeditor configuration