.dateTime()

Passes for the extended format, such as 2026-06-17, 2026-06-17 12:00 or 2026-06-17T12:00:00.000Z. Impossible dates and times such as 2023-02-30 or 25:00 fail, and so does the basic format without separators, 20260617. Every accepted string is also accepted by DateTime.parse.

Signature

StringValidator<O> dateTime({String? message, MessageBuilder? messageBuilder})

Parameters

Parameter	Type	Meaning
message	String?	Replaces the default error message.
messageBuilder	MessageBuilder?	Builds the message from the issue. message wins when both are given. See Message builders.

Issue

Code invalidDateTime. Default message: value must be a valid date. value is replaced by the field name when there is one.

Code generation

@IsDateTime(), or the constant @isDateTime. A DateTime parameter, nullable or not, gets .dateTime() without any annotation, because JSON carries dates as strings. DateTime elements of lists and maps get it too. Put the annotation on the constructor parameter or the field.

Example

Hand-written

final date = l.string().dateTime();

Generated

required DateTime createdAt, // l.string().dateTime().required()
DateTime? deletedAt,         // l.string().dateTime()

date.validate(input)+2-3

1. +valid: '2026-10-04'
2. +valid: '2026-10-04T10:15:00Z'
3. -invalid: '2023-02-30'value must be a valid date
4. -invalid: '20261004'value must be a valid date
5. -invalid: 'yesterday'value must be a valid date