tel[phone]

tel[phone] is a string that resembles a telephone number or a tel URI fragment. It is not a registered or routable number in any telecommunication network.

In documentation and software development, such arbitrary strings are used as placeholders for testing interfaces, forms, and datasets. They help demonstrate input fields, validation behavior, and data pipelines without involving real users or numbers.

If treated as a tel URI, the RFC 3966 standard defines tel URIs as tel:[phone]. In practice, telephone numbers include a country code and may be formatted with spaces, dashes, or other separators. Without a proper country code or formatting, tel[phone] does not conform to international numbering conventions such as E.164.

Because tel[phone] is not tied to a real number, it avoids exposing private information and can be safely used in samples. When deploying in production, developers should validate, normalize, and format numbers according to local rules and privacy requirements.

See also: E.164 numbering plan; RFC 3966; telephone numbering in software.