Sometimes you don't want a separate file request. You've got a tiny logo, a single emoji SVG, or a short audio clip, and spinning up another HTTP request for each one just slows the page. Base64 data URLs let you paste the file's contents directly into your HTML, CSS, or JSON as text.
The catch with "convert file to Base64" sites is the same as always: you're uploading the file to get text back. The File to Base64 tool does it on your device. Load a file and it returns a data URL you can copy or download as text; flip to the other mode and paste Base64 to recover the original file and download it. Nothing is sent anywhere.
A practical rule: Base64 makes a file about 33% larger, so it only pays off for small assets. Inlining a 4 KB icon saves a request; inlining a 400 KB photo just bloats your markup. Use it for icons, small SVG, and the occasional data snippet you want to keep self-contained.
If you're not sure how big the result will be, the File Info tool reports the source size first, so you can decide whether inlining is worth it.
Quick path: open File to Base64, load the small file, copy the data URL into your stylesheet or markup, and ship one fewer request.