How to allow download of .json file with ASP.NET

How can I enable the download of *.json files from an old ASP.NET site (IIS6 I am led to believe)?

I am getting a 404 page instead of the JSON file.

Do I need to create a web.config file? What goes in it?


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Method 1

If you want to manually add support to your site, you can just add the following to your web.config in the system.webServer section:

    <mimeMap fileExtension=".json" mimeType="application/json" />

This will add a “local” configuration under IIS. This does not work in IIS6, but does work in IIS7 and newer.

Method 2

Add the JSON MIME type to IIS 6. Follow the directions at MSDN’s Configure MIME Types (IIS 6.0).

  • Extension: .json
  • MIME type: application/json

Don’t forget to restart IIS after the change.

UPDATE: There are easy ways to do this on IIS7 and newer. The op specifically asked for IIS6 help so I’m leaving this answer as-is. But this answer is still getting a lot of traffic even though IIS6 is very old now. Hopefully you’re using something newer, so I wanted to mention that if you have a newer IIS7 or newer version see @ProVega’s answer below for a simpler solution for those newer versions.

Method 3

Solution is you need to add json file extension type in MIME Types

Method 1

Go to IIS, Select your application and Find MIME Types

How to allow download of .json file with ASP.NET

Click on Add from Right panel

File Name Extension = .json

MIME Type = application/json

How to allow download of .json file with ASP.NET

After adding .json file type in MIME Types, Restart IIS and try to access json file

Method 2

Go to web.config of that application and add this lines in it

     <mimeMap fileExtension=".json" mimeType="application/json" />

Method 4

When adding support for mimetype (as suggested by @ProVega) then it is also best practice to remove the type before adding it – this is to prevent unexpected errors when deploying to servers where support for the type already exists, for example:

    <remove fileExtension=".json" />
    <mimeMap fileExtension=".json" mimeType="application/json" />

Method 5

Just had this issue but had to find the config for IIS Express so I could add the mime types. For me, it was located at C:Users<username>DocumentsIISExpressconfigapplicationhost.config and I was able to add in the correct “mime map” there.

Method 6

  1. Navigate to C:UsersusernameDocumentsIISExpressconfig
  2. Open applicationhost.config with Visual Studio or your favorite text-editor.
  3. Search for the word mimeMap, you should find lots of ’em.
  4. Add the following line to the top of the list: .

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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