Novak.Net

Realistic, internally consistent Czech test data for .NET: people with names, rodné číslo, e-mails, phone numbers, real postal addresses and valid bank accounts.

using Novak.Net;

var faker = new NovakClient(seed: 42);       // same data on every run
var p = faker.People.GeneratePerson();

// e.g. Iveta Poláková, 536118/944, iveta.polakova@gmail.com, +420722249673
// Holcova 1289, 530 02 Pardubice
// 1260367954/6363 (Partners Banka), CZ1963630000001260367954

• Correct Czech rules. Feminine surnames (Novák → Nováková, Vaněk → Vaňková, Černý → Černá). Rodné číslo with every historical rule. Account numbers using the CNB mod-11 checksum, with IBAN and BIC.
• Real reference data. 20,000 real addresses from the RÚIAN register, weighted by population. The official CNB bank code list, weighted by market share. Real mobile and landline ranges from the ČTÚ numbering plan. The most common Czech names, weighted by frequency.
• Consistent people. The rodné číslo encodes the person's birth date and gender, and the e-mail is built from the name.
• Deterministic. Seed the whole client for reproducible sequences, or seed a single call.
• Modular. Use the Novak.Net facade, or reference only the packages you need.

Install

dotnet add package Novak.Net

Targets .NET 8 and .NET 10. No dependencies outside the Novak.Net.* packages.

Package	Contents
Novak.Net	NovakClient facade and the Person generator. References all modules below.
Novak.Net.Names	First names, surnames, full names. docs
Novak.Net.Emails	Name-based e-mail addresses. docs
Novak.Net.PhoneNumbers	+420 mobile and landline numbers. docs
Novak.Net.Addresses	Real RÚIAN postal addresses. docs
Novak.Net.RodneCislo	Birth number generator, validator and parser. docs
Novak.Net.BankAccounts	Account numbers, IBAN, BIC, validator. docs
Novak.Net.Common	Shared randomness primitives.

People

using Novak.Net.People;
using Novak.Net.Addresses.Models;
using Novak.Net.Names.Models;

var person = faker.People.GeneratePerson(new PersonGeneratorOptions
{
    Gender = Gender.Female,
    MinAge = 25,
    MaxAge = 40,
    Region = CzechRegion.Jihomoravsky,   // or City = "Brno"
    SafeEmailDomains = true,             // example.com / .net / .org only
});

person.FullName;                    // "Kateřina Dvořáková"
person.BirthDate;                   // 1991-04-17
person.RodneCislo.Value;            // "915417/2489" (matches the birth date and gender)
person.Email.Value;                 // "katerina.dvorakova@example.com"
person.Phone.ToString(PhoneNumberFormat.International); // "+420 731 234 567"
person.Address.ToMultiline();       // "Arménská 506/11\n625 00 Brno"
person.BankAccount.ToIban(spaced: true);

Ages are computed against today unless you set ReferenceDate. Set it if a seeded person must stay identical on every day your tests run.

Determinism

var faker = new NovakClient(seed: 123);    // all generators share one seeded sequence
faker.Names.GenerateFullName();            // differs on each call, identical on every run

faker.Names.GenerateFullName(new NameGeneratorOptions { Seed = 7 }); // pinned: always the same value

Every generator also has a constructor that accepts an optional IRandom. A seeded sequence is reproducible on a given .NET major version, because System.Random does not guarantee the same sequence across runtime versions.

Individual generators

Every generator works without arguments and has an options object.

new NameGenerator().GenerateName(new NameGeneratorOptions { Gender = Gender.Male });            // Jakub Novotný
new EmailGenerator().GenerateEmail(new EmailGeneratorOptions { FirstName = "Jiří", LastName = "Říha" }); // jiri.riha@seznam.cz
new PhoneNumberGenerator().GeneratePhoneNumber();                                                // +420603123456
new AddressGenerator().GenerateAddress(new AddressGeneratorOptions { City = "Praha 5" });      // Barrandovská 346/58, 152 00 Praha 5
new RodneCisloGenerator().Generate(new RodneCisloGeneratorOptions { BirthDate = new(1985, 2, 28) });
new BankAccountGenerator().GenerateBankAccount(new BankAccountGeneratorOptions { BankCode = "0800" });

RodneCisloGenerator.Validate("736028/5163");     // true
BankAccountGenerator.Validate("19-2000145399/0800"); // true

Run the sample

dotnet run --project samples/Novak.Net.Sample -- 42

Build and test

dotnet build
dotnet test

Tests use TUnit on Microsoft.Testing.Platform (configured in global.json).

A note on realism

Generated values can coincide with real ones. The addresses are real buildings, valid phone numbers and e-mail addresses may belong to someone, and a random account number can exist. Treat the data as test data. Don't send e-mails, SMS or payments to it from a system that can reach the outside world. For that case, use SafeDomains/SafeEmailDomains, or your own AllowedDomains.

Data sources and licences

The code is MIT-licensed. The bundled reference data comes from public Czech open data, listed in THIRD-PARTY-NOTICES.md. Addresses come from RÚIAN (© ČÚZK, CC BY 4.0) and bank codes come from the Czech National Bank. Run tools/build_address_data.py to regenerate the address sample from a newer RÚIAN export.