MIME Type Lookup

Find your file's extension, copy the MIME string from the second column, and set it as the Content-Type header value in your server config or API response. The strings here are the registered forms, so they're safe to use verbatim as a content type lookup result.

The full string is application/vnd.openxmlformats-officedocument.wordprocessingml.document, which nobody memorizes. The modern Office formats all use these long vnd.openxmlformats names, and the spreadsheet and presentation variants differ only near the end, which is exactly why a lookup beats recall.

Because RFC 9239 settled the question in 2022: text/javascript is the standard type, and application/javascript is now obsolete though still widely recognized. Browsers accept both, but new configs should emit text/javascript, which is what this table shows for .js and .mjs.

It's honest but blunt: it declares arbitrary binary data, so browsers respond by downloading the file rather than attempting to display it. Use it as a fallback for genuinely unknown content, never for anything you want rendered inline, like images or PDFs.

Yes. Alongside the classics you'll find .webp as image/webp, .avif as image/avif, and .heic as image/heic, the iPhone camera format that trips up upload validators expecting only JPEG and PNG.

Yes, the Font group covers .woff, .woff2, .ttf, and .otf with their font/ prefixed types. Serving the correct one matters in practice because font requests interact with CORS and preload hints, where a mismatched type can silently cancel the optimization.

application/json, listed under the Data group. Some frameworks append a charset parameter, which is harmless, but JSON is defined as UTF-8 so the bare type is enough. Avoid text/json entirely, since it was never a registered type.