RestSharp vs CurlDotNet (curl for C#)

RestSharp vs CurlDotNet (curl for C#): both are .NET HTTP client libraries, but they start from different places. RestSharp wraps HttpClient in a request/response object model. CurlDotNet runs curl commands, so anything documented as a curl ... line works unchanged, and also offers a fluent builder and a reusable client for code that is written by hand. This page compares the two side by side and ends with a migration checklist.

Key differences

  RestSharp CurlDotNet
Primary input RestRequest object curl command string, CurlRequestBuilder, or LibCurl
Client lifetime RestClient instance per base URL Static Curl.* for one-offs; LibCurl or CurlApiClient for shared config
Response RestResponse / RestResponse<T> CurlResult, ParseJson<T>()
HTTP errors IsSuccessful == false, optional ThrowOnAnyError IsSuccess == false, optional EnsureSuccess()
Serializer Pluggable (System.Text.Json, Newtonsoft, XML) System.Text.Json on .NET 8+, Newtonsoft.Json on .NET Standard 2.0
Interceptors Yes No; compose in your own code or use CurlSettings
Copy from API docs Translate by hand Paste the curl command
Native dependencies None None (pure C#)

GET request

RestSharp:

var client = new RestClient("https://httpbin.org");
var request = new RestRequest("get");
var response = await client.ExecuteAsync(request);
Console.WriteLine(response.Content);

CurlDotNet:

using CurlDotNet;

var result = await Curl.ExecuteAsync("curl https://httpbin.org/get");
Console.WriteLine(result.Body);

using CurlDotNet.Core;

var result = await CurlRequestBuilder.Get("https://httpbin.org/get").ExecuteAsync();

POST JSON

RestSharp:

var request = new RestRequest("post", Method.Post)
    .AddJsonBody(new { name = "Ada", age = 36 });
var response = await client.ExecuteAsync(request);

CurlDotNet:

var result = await Curl.ExecuteAsync(@"curl -X POST https://httpbin.org/post
    -H 'Content-Type: application/json'
    -d '{""name"":""Ada"",""age"":36}'");

var result = await CurlRequestBuilder.Post("https://httpbin.org/post")
    .WithJson(new { name = "Ada", age = 36 })
    .ExecuteAsync();

Headers and query parameters

RestSharp:

var request = new RestRequest("get")
    .AddHeader("Accept", "application/json")
    .AddQueryParameter("page", "2")
    .AddQueryParameter("per_page", "50");

CurlDotNet puts query parameters in the URL, as curl does:

var result = await Curl.ExecuteAsync(
    "curl -H 'Accept: application/json' 'https://httpbin.org/get?page=2&per_page=50'");

var result = await CurlRequestBuilder.Get("https://httpbin.org/get?page=2&per_page=50")
    .WithHeader("Accept", "application/json")
    .ExecuteAsync();

Authentication

RestSharp:

var client = new RestClient(new RestClientOptions("https://httpbin.org")
{
    Authenticator = new HttpBasicAuthenticator("user", "passwd")
});
// or: new JwtAuthenticator("token123")

CurlDotNet:

var basic  = await Curl.ExecuteAsync("curl -u user:passwd https://httpbin.org/basic-auth/user/passwd");
var bearer = await Curl.ExecuteAsync("curl -H 'Authorization: Bearer token123' https://httpbin.org/bearer");

var basic  = await CurlRequestBuilder.Get("https://httpbin.org/basic-auth/user/passwd")
    .WithBasicAuth("user", "passwd").ExecuteAsync();
var bearer = await CurlRequestBuilder.Get("https://httpbin.org/bearer")
    .WithBearerToken("token123").ExecuteAsync();

Typed responses

RestSharp:

var response = await client.ExecuteAsync<Slideshow>(new RestRequest("json"));
var slideshow = response.Data;

CurlDotNet:

var result = await Curl.ExecuteAsync("curl https://httpbin.org/json");
var slideshow = result.ParseJson<SlideshowResponse>();

ParseJson<T>() matches property names case-insensitively on every target, like RestSharp’s default serializer, so camelCase JSON binds to PascalCase properties; annotate properties with [JsonPropertyName("...")] only when the API uses snake_case or other names that differ by more than case. When you do not want a class, parse result.Body with JsonDocument.

File upload

RestSharp:

var request = new RestRequest("post", Method.Post)
    .AddFile("file", "report.pdf")
    .AddParameter("title", "Report");

CurlDotNet:

var result = await Curl.ExecuteAsync("curl -F 'title=Report' -F 'file=@report.pdf' https://httpbin.org/post");

var result = await CurlRequestBuilder.Post("https://httpbin.org/post")
    .WithMultipartForm(
        fields: new Dictionary<string, string> { ["title"] = "Report" },
        files:  new Dictionary<string, string> { ["file"] = "report.pdf" })
    .ExecuteAsync();

Timeout and retries

RestSharp:

var client = new RestClient(new RestClientOptions("https://httpbin.org")
{
    Timeout = TimeSpan.FromSeconds(30)
});
// retries: typically Polly around ExecuteAsync

CurlDotNet (no timeout applies unless you set one, as with curl):

var result = await Curl.ExecuteAsync("curl -m 30 https://httpbin.org/delay/2");

Retries need no Polly: curl’s --retry retries timeouts and HTTP 408/429/500/502/503/504 with doubling back-off and honours Retry-After, and CurlSettings.WithRetries retries any failure. See curl –retry in C#.

var result = await Curl.ExecuteAsync("curl -m 30 --retry 3 https://httpbin.org/status/503");

var settings = new CurlSettings().WithTimeout(30).WithRetries(count: 3, delayMs: 1000);
var result2 = await Curl.ExecuteAsync("curl https://httpbin.org/status/503", settings);

Error handling

RestSharp:

var response = await client.ExecuteAsync(request);
if (!response.IsSuccessful)
    Console.WriteLine($"{(int)response.StatusCode}: {response.ErrorMessage}");

CurlDotNet:

using CurlDotNet.Exceptions;

try
{
    var result = await Curl.ExecuteAsync("curl -m 10 https://httpbin.org/status/500");
    if (!result.IsSuccess)
        Console.WriteLine($"HTTP {result.StatusCode}: {result.Body}");
}
catch (CurlException ex)   // DNS, connect, timeout, SSL failures
{
    Console.WriteLine($"curl error {ex.CurlErrorCode}: {ex.Message}");
}

Add -f to the command if you want HTTP errors to throw (CurlHttpReturnedErrorException, curl exit code 22), similar to RestSharp’s ThrowOnAnyError.

Shared client and dependency injection

RestSharp:

services.AddSingleton(_ => new RestClient("https://api.github.com"));

CurlDotNet offers two options. CurlApiClient is the closest equivalent to a RestClient bound to a base URL:

using CurlDotNet;

services.AddSingleton(_ => new CurlApiClient("https://httpbin.org"));

// usage
var created = await api.PostJsonAsync("/post", new { name = "Ada" });
var fetched = await api.GetAsync("/get");

LibCurl carries default headers, auth, proxy and timeouts across any URL:

using CurlDotNet.Lib;

services.AddSingleton(_ => new LibCurl()
    .WithUserAgent("MyApp/1.0")
    .WithBearerToken(token)
    .WithTimeout(TimeSpan.FromSeconds(20)));

What RestSharp has that CurlDotNet does not

What CurlDotNet has that RestSharp does not

Migration checklist