RestAssured.Net brings the well loved REST Assured style to C# and the .NET platform. If you have seen the given, when, then flow in Java, this is the same idea for a .NET codebase, with a fluent way to build a request, send it and pull values out of the response with JSON path. In this project it runs on NUnit, the long standing .NET test framework.
How it works
You build a request with Given, attach a body, send it with a verb like Post, then assert on the status and extract fields from the response. The example posts a login and reads the token back out:
var payload = new Dictionary<string, string>
{
{ "email", "[email protected]" },
{ "password", "welcome01" }
};
var response = Given()
.Body(payload)
.Post($"{BaseUrl}/users/login");
response.StatusCode(HttpStatusCode.OK);
var accessToken = response.Extract().Body("$.access_token");
Assert.That(accessToken, Is.Not.Null);
The base URL is a constant in each fixture. For protected calls an NUnit [SetUp] method logs in and captures the token, and the invoices test then calls the endpoint with .OAuth2(token). Responses can be deserialized into typed C# models with Newtonsoft.Json, so a brands response becomes a real List of Brand objects. You run the suite with dotnet test, and it can emit an HTML report.
Benefits
For a .NET shop this is the natural choice, because tests are ordinary C# that live beside the application code. The fluent syntax is readable, JSON path extraction is convenient, and deserializing into typed models gives you compile time safety and clean assertions. NUnit is mature and well supported, and the whole thing builds and runs through the standard dotnet command line, so it drops into any pipeline without special handling.
Downsides
You need the .NET toolchain and comfort with C#, so it is not a starting point for someone coming from a graphical client. As with the Java libraries, JVM style startup and compilation make the loop slower than a lightweight script. One thing worth calling out from this example: the invoices test asserts an exact count of fifteen invoices, while the Java versions assert at least fifteen. An exact count is stricter and can turn brittle if the seeded data changes, so choose exact or at least deliberately rather than by accident.
What the example project tests
The repository at github.com/testsmith-io/api-test-automation-csharp-nunit-restassurednet tests the Practice Software Testing API at https://api.practicesoftwaretesting.com, the ToolShop backend used across this series.
Three scenarios are covered. A login test posts credentials to /users/login and asserts a 200 with a non null access_token. A brands test calls GET /brands, deserializes the result into a list of brand models, and checks for at least two. A protected invoices test logs in during setup, sends the token with .OAuth2, calls GET /invoices, and checks the returned list. A GitHub Actions workflow runs dotnet format to verify formatting and dotnet test on push and on a weekly cron, then uploads the HTML result. The scenarios match the Java REST Assured example, which makes for a clean comparison across the two platforms.