Validation rules

Every value a website user submits is checked before it reaches a record. The rules are per record type and per field, and the same rules apply whether a whole record or a single field was submitted.

How a save is validated

Save	Checked
A whole record	Every field listed below for that record type. A field the payload does not carry takes its default, which is the empty value, so a required field that is left out is reported as empty.
A single field	Only that field. The rules of the other fields are not evaluated at all, so an inline save of one field never reports a different one as missing.

The list of fields below is at the same time the list of names a save may address. A name that is not in it is refused with 400 rather than ignored, so uid, pid, hidden, the image and the owning website user have no path into a record through a save.

Profile

Field	Rule	Message id
`shortname`	Required.	`validation.profile.shortname.empty`
`shortname`	Between 2 and 255 characters.	`validation.profile.shortname.length`
`firstname`	Optional, at most 255 characters.	`validation.profile.firstname.tooLong`
`lastname`	Optional, at most 255 characters.	`validation.profile.lastname.tooLong`
`birthday`	Optional. When given, a date in the format `YYYY-MM-DD`.	`validation.profile.birthday.invalid`
`bio`	Optional, at most 5000 characters.	`validation.profile.bio.tooLong`

The 255 character bounds are the length of the varchar(255) columns the values are stored in. The 5000 character bound of the biography is not a column limit — the column is a text column — it bounds the request payload.

A birthday is a date and nothing else: a value carrying a time of day is rejected rather than truncated, and a date that does not exist, such as 2026-02-30, is rejected rather than rolled forward. An empty value means "no birthday" and passes.

Postal address

Field	Rule	Message id
`type`	One of `home`, `work`, `others`. An empty value is refused as well.	`validation.address.type.invalid`
`line1`	Required.	`validation.address.line1.empty`
`line1`	At most 255 characters.	`validation.address.line1.tooLong`
`line2`	Optional, at most 255 characters.	`validation.address.line2.tooLong`

E-mail address

Field	Rule	Message id
`type`	One of `private`, `business`, `others`. An empty value is refused as well.	`validation.email.type.invalid`
`email`	Required.	`validation.email.email.empty`
`email`	A valid e-mail address.	`validation.email.email.invalid`
`email`	At most 255 characters.	`validation.email.email.tooLong`

Two further ids exist and are shown only by a rule that names no message of its own. No rule shipped with this extension does, so they appear once a rule set is changed:

Message id	Belongs to
`validation.choice.invalid`	The value-set check used by the two `type` fields.
`validation.date.invalid`	The date check used by `birthday`.

The messages of a rejected image upload are listed in Image upload.

Overriding the messages

All ids above are trans-unit ids in EXT:modern_extbase_frontend_edit/Resources/Private/Language/locallang.xlf. A translation is added the usual way, as a language file next to the English one. Changing the English wording, or the wording of an already translated language, is done with a resource override in config/system/settings.php or additional.php.

The configuration path for this differs between the supported TYPO3 versions. On TYPO3 v13:

config/system/additional.php, TYPO3 v13

$GLOBALS['TYPO3_CONF_VARS']['SYS']['locallangXMLOverride']['EXT:modern_extbase_frontend_edit/Resources/Private/Language/locallang.xlf'][]
    = 'EXT:my_sitepackage/Resources/Private/Language/Overrides/modern_extbase_frontend_edit.xlf';

On TYPO3 v14 that path was renamed, and the old one is no longer read:

config/system/additional.php, TYPO3 v14

$GLOBALS['TYPO3_CONF_VARS']['LANG']['resourceOverrides']['EXT:modern_extbase_frontend_edit/Resources/Private/Language/locallang.xlf'][]
    = 'EXT:my_sitepackage/Resources/Private/Language/Overrides/modern_extbase_frontend_edit.xlf';

Both accept a list, so several override files can be stacked, and both accept a locale as an additional first key to override one language only.

Note

The TypoScript _LOCAL_LANG mechanism does not reach these labels. Validation messages are resolved by the validators themselves, through the fully qualified label reference rather than through a plugin's language context, and only a resource override applies there.

Messages carrying a number take it from the rule rather than from the text, through positional placeholders. %1$s and %2$s in the shortname length message are the lower and the upper bound; every other length message carries a single %1$s, which is the upper bound. Keep the placeholders and their order when rewriting a message.