HTTPREF
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MIME Type

application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

Office

Standard MIME type for modern Excel XLSX spreadsheet files.

MIME type reference, HTTP example, browser usage, common mistakes, and related content.

What is the application/vnd.openxmlformats-officedocument.spreadsheetml.sheet MIME type?

The MIME type application/vnd.openxmlformats-officedocument.spreadsheetml.sheet is used to tell browsers, APIs, and servers how a file or response body should be interpreted.

MIME stands for Multipurpose Internet Mail Extensions, and MIME types are now a standard part of HTTP responses and web content delivery.

When a browser or client receives a response with application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, it uses that information to decide how the content should be processed, rendered, downloaded, or executed.

Example

Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

HTTP example

HTTP/1.1 200 OK
Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Content-Length: 1256

Common file extensions

.xlsx

Common use cases

  • Spreadsheet exports
  • Business reporting
  • Downloadable XLSX files

Common mistakes

  • Using the wrong MIME type for the file being served
  • Returning text/plain instead of application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
  • Forgetting required parameters like charset when relevant
  • Using a deprecated MIME type in older server configurations
  • Serving assets with a mismatched Content-Type header, causing browser parsing issues

How browsers use it

Browsers use the Content-Type response header to decide how a response should be handled. For example, HTML is rendered as a page, CSS is parsed as styles, JavaScript is executed as script, and images are displayed visually. If the MIME type is incorrect, the browser may refuse to load the file correctly or may treat it as plain text or a download instead.

Developer note

Important if your app generates Excel reports or downloadable spreadsheets.

Related MIME types

application/vnd.ms-exceltext/csvapplication/pdf