All ASP.NET Web API controllers return 404

Question

I'm trying to get an API Controller to work inside an ASP.NET MVC 4 web app. However, every request results in a 404 and I'm stumped. :/

I have the standard API controller route from the project template defined like:

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );
    }
}

The registration is invoked in Global.asax:

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();

    // Register API routes
    WebApiConfig.Register(GlobalConfiguration.Configuration);

    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);

    RouteConfig.RegisterRoutes(RouteTable.Routes);
}

I have a basic API controller like this:

namespace Website.Controllers
{
    public class FavoritesController : ApiController
    {       
        // GET api/<controller>
        public IEnumerable<string> Get()
        {
            return new [] { "first", "second" };
        }

        // PUT api/<controller>/5
        public void Put(int id)
        {

        }

        // DELETE api/<controller>/5
        public void Delete(int id)
        {

        }
    }
}

Now, when I browse to localhost:59900/api/Favorites I expect the Get method to be invoked, but instead I get a 404 status code and the following response:

<Error>
   <Message>
       No HTTP resource was found that matches the request URI 'http://localhost:59900/api/Favorites'.
   </Message>
   <MessageDetail>
      No type was found that matches the controller named 'Favorites'.
   </MessageDetail>
</Error>

Any help would be greatly appreciated, I'm losing my mind a little bit over here. :) Thanks!

Have you tried testing your routes with Phil Haack's Route Tester? haacked.com/archive/2008/03/13/url-routing-debugger.aspx — Robert Harvey
– Robert Harvey, Commented Mar 21, 2013 at 19:07
The route tester says the /api/Favorites request matches the api/{controller}/{id} route pattern. However, there are other external routes that match higher up in the list. Perhaps those routes are intercepting my requests... — Ted Nyberg
– Ted Nyberg, Commented Mar 21, 2013 at 19:15
why are you overriding Application_Start? By default that method will register what you have in your overridden method. Maybe the routes being registered twice is causing problems. — nitewulf50
– nitewulf50, Commented Mar 21, 2013 at 19:21
I have an abstract base class that I'm inheriting. I've tried skipping the inheritance, but the result remains the same. Thanks for the help, though! I'll edit the question to get rid of any confusion. :) — Ted Nyberg
– Ted Nyberg, Commented Mar 21, 2013 at 19:23

Eric Bishard · Accepted Answer · 2014-12-15 06:03:28Z

146

One thing I ran into was having my configurations registered in the wrong order in my GLobal.asax file for instance:

Right Order:

AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);

Wrong Order:

AreaRegistration.RegisterAllAreas();
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
WebApiConfig.Register(GlobalConfiguration.Configuration);

Just saying, this was my problem and changing the order is obvious, but sometimes overlooked and can cause much frustration.

answered Dec 15, 2014 at 6:03

Eric Bishard

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8 Comments

Eric Bishard Over a year ago

I love the fact that my answer has helped a lot of people in a thread where it wasn't marked as the right question and the question asker says there is nothing wrong with the code in his question. I'm suggesting him changing the order of this Global.asax and marking mine correct. lol jk! But I am glad it has helped others out!

Eric Bishard Over a year ago

I think that this answer is most up voted because people who come to this question are more than likely having the problem with the order as I have shown here how to do. But I don't think it is an answer to this question. I provided it as an alternate answer because I knew people coming here would most likely have the same problem I had. I do appreciate your request though! lol

Wachburn Over a year ago

it's because RouteConfig has more universal route and it slams WebApiConfig's route?

SomeShinyObject Over a year ago

Just curious, in MVC5, the readme states after first creating an API controller to add in GlobalConfiguration.Configure(WebApiConfig.Register); on Global.asax.cs. I notice here that you have WebApiConfig.Register(GlobalConfiguration.Configuration);. Maybe I should just read the docs but does it make a difference which way you do it?

ᴍᴀᴛᴛ ʙᴀᴋᴇʀ Over a year ago

@SomeShinyObject if we do it the way in the answer we have to add GlobalConfiguration.Configuration.EnsureInitialized();. Doing it as GlobalConfiguration.Configure(WebApiConfig.Register); we don't.

|

Zenilogix · Accepted Answer · 2015-02-24 03:49:33Z

17

Had essentially the same problem, solved in my case by adding:

<modules runAllManagedModulesForAllRequests="true" />

to the

<system.webServer>

</system.webServer>

section of web.config

answered Feb 24, 2015 at 3:49

Zenilogix

1,4131 gold badge15 silver badges35 bronze badges

2 Comments

Kevin Harker Over a year ago

I found that this helped me, but after doing more research I found that you should not enable this without understanding what it means. Looking at this page on msdn it says "If your website is running on IIS 7 and if IIS has been updated, you do not need to set runAllManagedModulesForAllRequests to true. In fact, setting it to true is not recommended". There is a patch available that will make this setting unnecessary.

Jonathas Sucupira Over a year ago

This fixed the issue of not being able to call a PATCH method in my project.

General Grievance · Accepted Answer · 2025-08-12 13:26:01Z

14

Basically, I had spelt "Controller" wrong at the end of my class name. Correcting it fixed my 404. Simple as that!

edited Aug 12 at 13:26

General Grievance

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answered Apr 16, 2015 at 11:49

user4796368

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Comments

zajonc · Accepted Answer · 2016-08-27 18:20:49Z

10

Add following line

GlobalConfiguration.Configure(WebApiConfig.Register);

in Application_Start() function in Global.ascx.cs file.

edited Aug 27, 2016 at 18:20

zajonc

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answered Aug 27, 2016 at 16:52

Farhan Anwar

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5 Comments

lmo Over a year ago

If this code answers the question, consider adding adding some text explaining the code in your answer. This way, you are far more likely to get more upvotes — and help the questioner learn something new.

Balint Bako Over a year ago

This solution worked for me with WebApi 2.0 however "WebApiConfig.Register(GlobalConfiguration.Configuration)" from the accepted answer threw an exception.

muhammad kashif Over a year ago

whats the difference between WebApiConfig.Register(GlobalConfiguration.Configuration) and your answer? Why it was not added in app start when project was first created?

vapcguy Over a year ago

@BalintBako Depending on the exception you got, you might've just needed to import the namespace at the top of the page: using System.Web.Http; - I had to do this, and then adding WebApiConfig.Register(GlobalConfiguration.Configuration); was fine. And I had to go into the WebApiConfig class and set the namespace to not have .App_Start on it, so that Global.asax.cs didn't have to have using MyProject.App_Start; added to the top of the page.

udorb b Over a year ago

best solution but need install ms web host or add ref.

Aran Dekar · Accepted Answer · 2016-12-01 04:16:18Z

7

I had the same problem, then I found out that I had duplicate api controller class names in other project and despite the fact that the "routePrefix" and namespace and project name were different but still they returned 404, I changed the class names and it worked.

answered Dec 1, 2016 at 4:16

Aran Dekar

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1 Comment

VictorySaber Over a year ago

I am so glad I read this. I too had everything separate but it returned 404. Changing the name of the controller fixed it.

BRass · Accepted Answer · 2017-12-04 20:34:44Z

5

Similar problem with an embarrassingly simple solution - make sure your API methods are public. Leaving off any method access modifier will return an HTTP 404 too.

Will return 404:

List<CustomerInvitation> GetInvitations(){

Will execute as expected:

public List<CustomerInvitation> GetInvitations(){

answered Dec 4, 2017 at 20:34

BRass

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Comments

Shakeer Hussain · Accepted Answer · 2016-10-14 14:52:07Z

4

Create a Route attribute for your method.

example

        [Route("api/Get")]
        public IEnumerable<string> Get()
        {
            return new string[] { "value1", "value2" };
        }

You can call like these http://localhost/api/Get

answered Oct 14, 2016 at 14:52

Shakeer Hussain

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1 Comment

vapcguy Over a year ago

Routing should be handled in the WebApiConfig automatically. This would only be needed if deviating from that pattern registered there.

Morvael · Accepted Answer · 2017-03-02 12:01:48Z

4

For reasons that aren't clear to me I had declared all of my Methods / Actions as static - apparently if you do this it doesn't work. So just drop the static off

[AllowAnonymous]
[Route()]
public static HttpResponseMessage Get()
{
    return new HttpResponseMessage(System.Net.HttpStatusCode.OK);
}

Became:-

[AllowAnonymous]
[Route()]
public HttpResponseMessage Get()
{
    return new HttpResponseMessage(System.Net.HttpStatusCode.OK);
}

answered Mar 2, 2017 at 12:01

Morvael

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Comments

user7885142 · Accepted Answer · 2018-06-11 07:13:56Z

3

Had this problem. Had to uncheck Precompile during publishing.

answered Jun 11, 2018 at 7:13

user7885142

Comments

Ted Nyberg · Accepted Answer · 2013-03-22 08:03:27Z

2

I'm a bit stumped, not sure if this was due to an HTTP output caching issue.

Anyways, "all of a sudden it started working properly". :/ So, the example above worked without me adding or changing anything.

Guess the code just had to sit and cook overnight... :)

Thanks for helping, guys!

answered Mar 22, 2013 at 8:03

Ted Nyberg

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2 Comments

Jon Davis Over a year ago

This sounds like "Build --> Clean" + "Build --> Rebuild" (and btw Rebuild does less than Clean+Build, Clean does more with temporary asp.net files cleanup)

JeffR Over a year ago

@JonDavis After a few hours of frustration...your comment helped me. The project I was working with was renamed in the past and it still had the old dll's in the folder. Build clean wouldn't clean them out but after I manually deleted them it's working now.

k2snowman69 · Accepted Answer · 2017-07-02 04:41:29Z

I'm going to add my solution here because I personally hate the ones which edit the web.config without explaining what is going on.

For me it was how the default Handler Mappings are set in IIS. To check this...

Open IIS Manager
Click on the root node of your server (usually the name of the server)
Open "Handler Mappings"
Under Actions in the right pane, click "View ordered list"

This is the order of handlers that process a request. If yours are like mine, the "ExtensionlessUrlHandler-*" handlers are all below the StaticFile handler. Well that isn't going to work because the StaticFile handler has a wildcard of * and will return a 404 before even getting to an extensionless controller.

So rearranging this and moving the "ExtensionlessUrlHandler-*" above the wildcard handlers of TRACE, OPTIONS and StaticFile will then have the Extensionless handler activated first and should allow your controllers, in any website running in the system, to respond correctly.

Note: This is basically what happens when you remove and add the modules in the web.config but a single place to solve it for everything. And it doesn't require extra code!

Marc Miller · Accepted Answer · 2022-06-30 12:26:21Z

2

I found this in a comment here: https://andrewlock.net/when-asp-net-core-cant-find-your-controller-debugging-application-parts/

Add the following to your Program.cs:

app.UseRouting();

app.UseEndpoints(endpoints =>
{
// DP: I don't know the purpose of this, but without it, all controllers report 404
endpoints.MapControllerRoute("default", "WTF is this");
});

For me this is all it took to make it work after hours of trying to find a solution. If this doesnt work for you, try adding

builder.Services.AddControllers();

answered Jun 30, 2022 at 12:26

Marc Miller

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1 Comment

Dadkhah Over a year ago

You can simply write app.MapControllerRoute("default","WTF is this"); Reference: learn.microsoft.com/en-us/aspnet/core/mvc/controllers/…

Kevin R. · Accepted Answer · 2016-03-12 22:11:05Z

1

Check that if your controller class has the [RoutePrefix("somepath")] attribute, that all controller methods also have a [Route()] attribute set.

I've run into this issue as well and was scratching my head for some time.

answered Mar 12, 2016 at 22:11

Kevin R.

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Comments

Stephen Rauch · Accepted Answer · 2017-10-27 02:41:17Z

1

WebApiConfig.Register(GlobalConfiguration.Configuration);

Should be first in App_start event. I have tried it at last position in APP_start event, but that did not work.

edited Oct 27, 2017 at 2:41

Stephen Rauch♦

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answered Oct 27, 2017 at 2:20

Ram

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1 Comment

vapcguy Over a year ago

This is basically the same as the accepted answer, but wrong because it doesn't have to be first, just ahead of the RouteConfig registration, because if you call your API with a route you are using for ApiController, it will assume you are actually trying to route with whatever you registered for Controller in RouteConfig, instead. I won't downvote, because if someone actually does this, it will work, but the reasoning is not correct.

ProjectAlice · Accepted Answer · 2023-06-05 07:38:13Z

1

If you are by any chance using the [Authorize] attribute, check if you are logged in. This was the problem in my case.

answered Jun 5, 2023 at 7:38

ProjectAlice

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1 Comment

General Grievance Aug 12 at 13:50

Probably has something to do with this, but If you're using Windows Authentication, you probably have add the correct system.web/authorization rules and system.webServer/security/authorization rules for the appropriate user groups.

Davoud Zeini · Accepted Answer · 2015-12-05 20:07:44Z

Add this to <system.webServer> in your web.config:

<handlers>
    <remove name="ExtensionlessUrlHandler-Integrated-4.0"/>
    <remove name="OPTIONSVerbHandler"/>
    <remove name="TRACEVerbHandler"/>
    <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler"
        preCondition="integratedMode,runtimeVersionv4.0"/>
</handlers>

Adding <modules runAllManagedModulesForAllRequests="true" /> also works but is not recommended due performance issues.

Pavel · Accepted Answer · 2016-06-07 11:03:12Z

0

I have solved similar problem by attaching with debugger to application init. Just start webserver (for example, access localhost), attach to w3wp and see, if app initialization finished correctly. In my case there was exception, and controllers was not registered.

answered Jun 7, 2016 at 11:03

Pavel

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Comments

Hartono Halim · Accepted Answer · 2016-10-11 13:56:33Z

I had the same 404 issue and none of the up-voted solutions here worked. In my case I have a sub application with its own web.config and I had a clear tag inside the parent's httpModules web.config section. In IIS all of the parent's web.config settings applies to sub application.

<system.web>    
  <httpModules>
    <clear/>
  </httpModules>
</system.web>

The solution is to remove the 'clear' tag and possibly add inheritInChildApplications="false" in the parent's web.config. The inheritInChildApplications is for IIS to not apply the config settings to the sub application.

<location path="." inheritInChildApplications="false">
  <system.web>
  ....
  <system.web>
</location>

nuander · Accepted Answer · 2020-03-17 22:15:19Z

0

I have dozens of installations of my app with different clients which all worked fine and then this one just always returned 404 on all api calls. It turns out that when I created the application pool in IIS for this client it defaulted to .net framework 2.0 instead of 4.0 and I missed it. This caused the 404 error. Seems to me this should have been a 500 error. Very misleading Microsoft!

answered Mar 17, 2020 at 22:15

nuander

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Comments

Tom · Accepted Answer · 2020-04-27 23:00:42Z

I had this problem: My Web API 2 project on .NET 4.7.2 was working as expected, then I changed the project properties to use a Specific Page path under the Web tab. When I ran it every time since, it was giving me a 404 error - it didn't even hit the controller.

Solution: I found the .vs hidden folder in my parent directory of my VS solution file (sometimes the same directory), and deleted it. When I opened my VS solution once more, cleaned it, and rebuilt it with the Rebuild option, it ran again. There was a problem with the cached files created by Visual Studio. When these were deleted, and the solution was rebuilt, the files were recreated.

bafsar · Accepted Answer · 2020-09-16 16:17:06Z

0

If you manage the IIS and you are the one who have to create new site then check the "Application Pool" and be sure the CLR version must be selected. In my situation, it had been selected "No Managed Code". After changed to v4.0 it started to work.

answered Sep 16, 2020 at 16:17

bafsar

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udorb b · Accepted Answer · 2023-01-12 18:05:06Z

0

i try above but not sucess all

add ms webhost and GlobalConfiguration.Configure(WebApiConfig.Register);

answered Jan 12, 2023 at 18:05

udorb b

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MRS · Accepted Answer · 2024-10-22 10:28:36Z

0

spending like 1 hour figuring out why my controller isn't working , and FINALLY the problem was a MISSING "s" :D i am new to .net so I'm practicing a little so I've created an empty controller and name it UserController instead of UsersController

SO always use the wizard to create your controller

answered Oct 22, 2024 at 10:28

MRS

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Comments

Basava Devargudi · Accepted Answer · 2025-10-13 11:57:30Z

0

I was facing similar issues with 404 error not found while running ASP .Net core WEB Api.

Solution : I create new Project of ASO .Net core Web API with Target .Net Framework Version 8.0.

It Worked!

answered Oct 13 at 11:57

Basava Devargudi

1

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