Validation

Shared input rules apply wherever a resource's Request Keys table or validation type references them. The resource contract defines whether a value is required, nullable, unique, or subject to additional constraints; a shared format does not change those requirements.

Email Addresses

An email value must contain one mailbox address using ASCII characters, valid mailbox syntax, and no more than 254 characters. Internationalized domains must already be encoded as Punycode. Unicode characters in the local part are not supported.

Whitespace, control characters, quoted local parts, comments, address literals, backslashes, and display names are rejected. A single-address field does not accept multiple addresses separated by commas. The email validator does not trim or rewrite an address to make it valid.

Value	Result
[e-mail]	Accepted syntax.
[e-mail]	Accepted Punycode domain.
user@bücher.test	Rejected Unicode domain.
user [e-mail]	Rejected whitespace within the address.
Name <[e-mail]>	Rejected display-name format.
user@[127.0.0.1]	Rejected address literal.

These rules validate the address format; they do not establish that the mailbox exists or can receive mail. A nullable field can accept null according to its endpoint contract. An update's treatment of null and omitted keys is documented on the affected resource.

Email Lists

A field documented as a comma-separated email list accepts a string containing one or more addresses. Every address must satisfy the Email Addresses rules. Whitespace around each comma-separated entry is ignored during validation, so [e-mail], [e-mail] is valid.

Empty entries are rejected, including leading commas, trailing commas, consecutive commas, and entries containing only whitespace. For example, [e-mail],,[e-mail] is invalid. The comma-separated list format is used by recipient-select options.

An endpoint that declares an array of email addresses uses one mailbox per array element instead. For example, the Form recipient field accepts ["[e-mail]", "[e-mail]"]; a comma-separated list inside one element is invalid.

Phone Numbers

Fields with the phone validation accept valid telephone numbers according to the applicable country numbering plan. Use international E.164 notation for API values: a leading +, the country calling code, and the number without spaces or parentheses, for example [phone].

National notation, such as 01701234567, needs an appropriate country context during validation. The field's default_country_code preselects the editor's country; it does not supply country context for a bare API value. International notation identifies the country within the value itself.

The validation's configuration can further limit accepted numbers:

• country_codes restricts numbers to the configured countries. An omitted, null, or empty list applies no country restriction.

• fixed_line and mobile select the accepted number categories. When either flag is enabled, the number must match a selected category; when neither is enabled, no category restriction is applied.

• A number must be valid for its country and satisfy the configured restrictions. A valid format does not establish that the number is assigned to a person or reachable.

Value	Result with German mobile numbers allowed
[phone]	Accepted international number.
01701234567	Requires German country context.
not-a-phone-number	Rejected.

The phone properties of Users and Contacts accept nullable strings. Configurable form, task, and additional-attribute fields apply these phone-number rules when the phone validation is attached. Required and nullable behavior follows the affected field's contract.

Related Input Rules

Attribute Set Keys define how sets are identified when values are assigned. System Variables define separate syntax for rendered expressions and key-only values.

FormFieldValidationTypes define the accepted configuration for field validations, including dates, numeric bounds, selections, files, and regular expressions. The same validation types apply to configurable form, task, and additional-attribute fields.

Assignment and Targeting defines the rules for static and computed recipients. Rich Text defines the shared HTML format for formatted text.