Number Information API Documentation

January 25, 2019 – v. 1.0.3

There is a newer version of the documentation available here.

Please contact us in the case of questions.

Front Invest DA
Postboks 2406 Solli
0201 OSLO
22 20 24 00
Org. nr: 983 203 213

Click here for product information and pricing (in Norwegian). You can also order or try our API for free.

Telephone Number Lookup

One can easily query a single Norwegian telephone number in our number information database.
The information is updated daily with the data supplied by the Norwegian telephone companies and is therefore always up to date.



:telephonenumber -> Norwegian telephone number E164 formatted (eg. +4798765432, note that the + sign must be URL-encoded as %2B).


Each query must employ HTTP basic authentication using an API key and password. The API key and password will be supplied by Front when your account is registered. Use these in a standard HTTP basic Authorization header. For example, if one has received the API key “Aladdin” and password “OpenSesame”, the value for the Authorization header should be the base 64 encoding of “Aladdin:OpenSesame” or QWxhZGRpbjpPcGVuU2VzYW1l.

Authorization: Basic QWxhZGRpbjpPcGVuU2VzYW1l


Valid telephone number

The response will be a JSON document with the number information:

    "address":"Storgata 10",
Hidden telephone number

If the number is registered as hidden from number information the response will not include any personal information:


These fields have the following meaning:
phoneBook: Can publish in a phone book (paper version)
manualQuery: Can access information for a manual query (telephone)
electronicQuery: Can access information for an electronic query (API/SMS)

Note: Some telephone companies remove the number from number information when the customer registers to hide their information. In this case the response will be the same as if the number is not in use.

Telephone number not found

If a number is not found, the server will respond with HTTP status 404 and a JSON document with an error message is returned:

    "code": "NotFoundError",
    "message": "Phone number not found"

Overview of the possible errors

CodeHTTP StatusDescription
InvalidCredentialsError401Invalid API key and/or password
AccountDisabledError401Account disabled due to missing payment or misuse
InvalidArgumentError409Invalid telephone number
NotFoundError404Telephone number not found or hidden
TooManyRequestsError429Quota for the number of queries in the period exceeded
RequestThrottledError429Too many queries in a short period
InternalError500Unexpected error occurred on the server
Document History
  • January 9, 2019: Added HTTP status for errors.
  • May 26, 2017: Initial revision.