What is the MIME type of .csv files?
The MIME type (media type) for Comma-separated values files with the .csv extension is text/csv. Add ; charset=utf-8 and, for Excel, a UTF-8 BOM at the start of the file so accented characters display correctly. Use Content-Disposition: attachment; filename="data.csv" to force a download.
Content-Type header
Content-Type: text/csv; charset=utf-8Text-based types should include a charset so the browser decodes characters correctly.
Server configuration
| Server | Configuration |
|---|---|
Nginx (mime.types or types {}) | text/csv csv; |
Apache (.htaccess) | AddType text/csv .csv |
IIS (web.config) | <mimeMap fileExtension=".csv" mimeType="text/csv" /> |
| Node.js / Express | res.type('csv') or res.setHeader('Content-Type', 'text/csv; charset=utf-8') |
| Amazon S3 | Set Content-Type: text/csv on the object (metadata), or pass --content-type text/csv to aws s3 cp |
Should .csv files be compressed?
Yes. Comma-separated values is text, so enabling gzip or Brotli for text/csv typically saves 50–80 % of the transfer size. Make sure your server’s compression list includes this type — check with the website compression test.
Why the MIME type matters
Browsers decide what to do with a response — render, run, play or download — from the Content-Type header, not the file extension. With X-Content-Type-Options: nosniff, a wrong type causes stylesheets and scripts to be blocked outright. For uploads, never trust the type sent by the client; check the file’s content (its magic bytes) on the server.
Frequently asked questions
What is the MIME type for .csv?
text/csv.How do I set the Content-Type for .csv in Nginx?
text/csv csv; is listed in the types block (usually in /etc/nginx/mime.types) and reload Nginx.