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Base64 Data URL ↔ File
Decode base64 data URLs to downloadable files with detected MIME type, or encode any file as a base64 data URL for embedding. Your data never leaves your browser.
How to use Base64 Data URL ↔ File
- 1
Pick a mode
Encode mode turns a file into a base64 data URL. Decode mode turns a data URL back into a file.
- 2
Provide the input
In Encode mode, drop any file. In Decode mode, paste a data: URL.
- 3
Read the metadata
Detected MIME type, size, and (for images) a preview are shown.
- 4
Copy or download
Copy the data URL to your clipboard, or download the decoded file.
Frequently asked questions
- Does this tool upload my file?
- No. Every parse, transform, and download runs entirely in your browser using JavaScript and Web Workers. The file never leaves your device — there is no upload endpoint and no server-side processing.
- What's the size limit on a data URL?
- Base64 encoding inflates the file by about 33 percent. Browsers and HTML parsers usually choke past a few megabytes — use data URLs for icons and small images, not for video.
- Why does my decoded file have a generic name?
- Data URLs don't carry filenames — only MIME type and the encoded bytes. The tool picks an extension from the MIME type so the download is recognizable.