Base64.
Encode and decode text, files or data URLs in Base64. Full UTF-8 support.
Base64 is the encoding to fit binary data into text-only places: emails, URLs, JSON, CSS. Paste text, get Base64. Paste Base64, get text. Works on small files too — useful for data URLs in CSS or HTML.
- Encode and decode both ways, instantly
- Full UTF-8 (accents, ñ, emojis)
- URL-safe mode (`-` and `_` instead of `+` and `/`)
- Drop a file and get its data URL
- Auto-detection of valid vs invalid input
- Quick copy of result
- 01Inline images in CSS as data:URL
- 02Basic Auth authorization headers
- 03URL tokens without problematic chars
- 04Decode a JWT (the payload part)
- 05Inspect binary content in a dump
base64.util.ar
We're finishing this one. Landing will live at base64.util.ar.
Why does `btoa()` break on accents?
`btoa()` only accepts ASCII (0–255). For UTF-8 you have to encode to bytes first with TextEncoder, then to Base64. We do it automatically.
What's URL-safe Base64?
Variant replacing `+` with `-` and `/` with `_` (which break URLs), and dropping the `=` padding. Used by JWT and many modern APIs.
Safe to paste a secret here?
Base64 is NOT encryption, just encoding. Anyone with the result trivially decodes it. If your "secret" is just Base64, consider it public.
Max file size?
Up to ~10 MB comfortably. Above that the browser may stall — use a CLI like `base64` for big files.