W3C Validator

Triggers: !validate, !w3v

Try it

Kagi would openhttps://validator.w3.org/check?uri=lorem+ipsum&charset=(detect+automatically)&doctype=Inline&group=0

Run !validate in Kagi

URL pattern: https://validator.w3.org/check?uri=query&charset=(detect+automatically)&doctype=Inline&group=0

Searches validator.w3.org, filed under Tools.