Understanding MIME Types and File Extensions

Have you ever uploaded a file and the browser didn’t open it correctly — maybe it downloaded instead of showing up on the screen? That usually happens because of something called a MIME type. 🧠 What Is a MIME Type? A MIME type (short for Multipurpose Internet Mail Extensions) tells the browser what kind of file it’s dealing with. For example: File Type MIME Type Extension HTML page text/html .html CSS file text/css .css JavaScript file application/javascript .js JPEG image image/jpeg .jpg, .jpeg PDF document application/pdf .pdf Word document application/vnd.openxmlformats-officedocument.wordprocessingml.document .docx When your web server sends a file, it includes a header like this: ...

October 30, 2025 · 2 min