application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
The MIME type for modern Excel (.xlsx) — Open XML inside a ZIP wrapper.
Typical extensions
Primary uses
- Distributing business data
- Reporting outputs
- Ingestion into tools like Power BI
In a browser
Downloads by default. Microsoft 365 renders inline for signed-in users.
On a server
`Content-Disposition: attachment` plus the correct extension keeps UX clear.
In email
Send as an attachment; mitigate CSV Injection when the file originates from user input.