Bogus — Realistic Fake Data Generator for .NET

Introduction

Bogus is a .NET port of the popular faker.js library, providing a fluent API for generating realistic fake data. It is widely used for seeding databases, populating test fixtures, and prototyping applications without relying on production data.

What Bogus Does

• Generates fake data across 50+ categories including names, addresses, finance, and lorem text
• Provides a strongly-typed fluent API for defining generation rules per property
• Supports 40+ locales for internationalized fake data
• Produces deterministic output with configurable seed values for reproducible tests
• Works with records, classes, and anonymous types in C#, F#, and VB.NET

Architecture Overview

Bogus uses a fluent builder pattern where Faker<T> maps generation rules to properties via lambda expressions. Under the hood, each data category (Name, Address, Commerce, etc.) is a dataset class loaded from locale-specific JSON files. A Mersenne Twister PRNG with optional seed ensures reproducibility.

Self-Hosting & Configuration

• Install via NuGet: dotnet add package Bogus
• No external services or configuration required — it is a pure library
• Set a seed with new Faker<T>().UseSeed(1234) for deterministic output
• Use Faker.GlobalUniqueIndex to track unique values across instances
• Add locale-specific data with new Faker<T>("de") or any supported locale code

Key Features

• Fluent API with full IntelliSense support in Visual Studio and Rider
• Over 50 built-in data generators (Phone, Company, Vehicle, Hacker, etc.)
• Supports complex object graphs with nested fakers
• Lightweight with no external dependencies
• Extensively tested with high community adoption across the .NET ecosystem

Comparison with Similar Tools

• Faker.js — The JavaScript original; Bogus is its .NET port with idiomatic C# API
• AutoFixture — Focuses on anonymous test data; Bogus produces human-readable realistic data
• NBuilder — Object builder for tests; less focus on realistic data categories
• GenFu — Simpler .NET fake data library; Bogus has more categories and locales

FAQ

Q: Can Bogus generate unique values? A: Yes, use the .UniqueIndex property or the f.IndexFaker to ensure uniqueness across generated instances.

Q: Does Bogus work with Entity Framework? A: Yes, it is commonly used in EF Core seed methods to populate databases with test data.

Q: How do I generate a list of fake objects? A: Call faker.Generate(100) to create a list of 100 fake objects in one call.

Q: Is Bogus suitable for production use? A: It is designed for testing, development, and demos — not for generating production data.

Sources

• https://github.com/bchavez/Bogus
• https://www.nuget.org/packages/Bogus