application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
XLSX is the default spreadsheet handoff for analysts and operators who need structured sheets without legacy binary baggage.
Content-Type header
Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheetHow teams usually encounter it
This page maps the media type to the file extensions and delivery behaviors developers usually care about: browser parsing, upload validation, cache correctness, and asset handling.
Compression signal
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet is usually already compressed or stored in a binary-heavy format, so extra transfer compression tends to help less.
Server config snippets
Use these when a server is missing the right extension-to-MIME mapping or you want the expected header to survive a proxy, CDN, or custom asset bucket setup.
types {
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet xlsx;
}AddType application/vnd.openxmlformats-officedocument.spreadsheetml.sheet .xlsxMagic bytes / file signature
When you need to validate uploads or investigate a mislabeled file, the signature often starts with 50 4B 03 04.
Operational shortcut
If a browser downloads this asset instead of rendering it correctly, check the response header first, then verify the extension mapping on your origin and edge cache. .xlsx is the fastest sanity check for teammates reviewing the file outside the app.
Related application types
application/json
JSON is the default payload format for APIs, config files, and web app data exchange, so its MIME type shows up in almost every modern stack.
.json .mapapplication/javascript
JavaScript responses tell browsers and runtimes to execute source code, so correct MIME headers matter for module loading and CSP-safe delivery.
.jsapplication/pdf
PDF keeps layout stable across platforms, which is why teams reach for it when contracts, reports, and print-ready assets cannot shift in transit.
.pdfapplication/xml
XML remains common in feeds, enterprise integrations, sitemaps, and document standards that rely on schema validation and explicit namespaces.
.xmlapplication/sql
SQL files package schema changes, seed data, and reproducible queries for database review and deployment workflows.
.sqlapplication/gzip
Gzip wraps compressed payloads for archives and transfer pipelines, making it common in download bundles and server-side asset packaging.
.gz