Currently there's only one utility in the library, IdentificationNumber, which lets you parse, validate and generate Norwegian National Identity Numbers. More utilities are coming!

The library targets .NET Standard 2.0 and .NET 5, which means it's supported on pretty much any .NET platform still supported by Microsoft.

The library supports parsing fødselsnummer, D-nummer and H-nummer. This is done through the various overloads of IdentificationNumber.Parse and IdentificationNumber.TryParse. There's also a few overloads of IsValid to validate that a string is a valid identification number (of a specified type). Additionally, there are convenience methods for parsing out date of birth (using TryParseDateOfBirth) and gender (using TryParseGender) directly.

Parsing is built on modern APIs such as ReadOnlySpan<T>, which makes it really fast and completely allocation free. See benchmarks below.

The results of the IsValidIdentificationNumberBenchmark on .NET 8:

The library also supports generating valid fødselsnummer, D-nummer and H-nummer. This is done through the various overloads of IdentificationNumber.Generate. These let you specify kind, gender, date of birth and/or a min- and max date. If you want to control the randomness of the generation, e.g. for unit testing, you can create your own instance of IdentificationNumber.Generator and pass in your own (seeded) Random instance. See this unit test as an example.

The results of the GenerateIdentificationNumberBenchmark on .NET 8: