Data formats

Fax Numbers

The safest, least ambiguous way to supply a fax number to the InterFAX API is the following:

+(country code)(area code)(fax number), for example: +12129874563


00(country code)(area code)(fax number), for example: 0012129874563

which consists of the following parts:

  • + symbol or the numbers 00
  • The international country calling code.
  • The area code with no local access prefix (except for Italy, where the local access prefix is required; e.g. Rome is 06)
  • The fax number


Date-times are expected to be ISO 8601-compliant. See the link for details, but generally speaking, a date-time should look like this:

(date as YYYY-MM-DD)T(time)(GMT offset), for example: 2001-12-31T21:34+02:00

which is made up of the following parts:

  • A date part, like 2001-12-31
  • The letter T as a separator
  • A time part, like 21:34
  • A GMT time zone offset, like +02:00 or -08:00, specifying in which time zone the time part above is provided. In the absence of a time zone offset, or if the offset is 00:00 the time part provided will be assumed to be given in GMT.

Please remember to urlEncode the datetime value in the URL.


Must be true or TRUE or false or FALSE (i.e., not numbers). If absent, a default of false is assumed.