Security & Encoding
Base64 Encoder / Decoder
Turn text or a file into Base64, or decode Base64 back into text and files. Pick a direction, choose standard or URL-safe output, then copy or download the result. Everything is computed locally — your data never leaves the page.
Direction & options
liveInput
0 charsEncoding reads the file’s raw bytes. Decoding expects a text file that contains Base64.
Result
0 charsHow it works
Encode converts UTF-8 text (or any file’s raw bytes) into Base64.
Decode turns Base64 back into bytes and, when those bytes are valid UTF-8,
into readable text. Decoding accepts the standard +/ alphabet, the URL-safe
-_ alphabet, missing padding, embedded whitespace and a leading
data:…;base64, prefix, so pasted values from many sources just work.
Invalid Base64 is reported as a friendly message instead of silently producing bad bytes.
Everything runs in the browser — nothing is uploaded — and the direction, options
and text can be shared through the URL fragment.
Practical uses
Encode text or bytes to Base64 and decode Base64 back to text, with a URL-safe alphabet.
Common ways to use it
- Inspect or produce a Basic authentication header value.
- Decode the payload of a data URL while debugging an embedded asset.
- Encode a file's raw bytes for embedding or transfer.
Encode then decode
Input
Hello (UTF-8 text)
Output
encodeText("Hello") = SGVsbG8=
decodeText("SGVsbG8=") = Hello
URL-safe bytes FB EF FF = --__Verified with the tool's own functions. Encoding the UTF-8 text Café gives Y2Fmw6k=. The standard alphabet encodes the bytes FB EF FF as ++// while the URL-safe alphabet gives --__.
Options that matter
- Direction — encode or decode.
- Source — Text or File; a decoded file can be downloaded as raw bytes.
- Output alphabet — standard +/ or URL-safe -_.
- Line breaks — wrap encoded output at 76 characters in MIME/PEM style.
- data: URL prefix — when encoding a file, prefix the output with its MIME type.
Things to keep in mind
- Base64 is an encoding, not encryption — it does not keep data secret.
- The URL-safe alphabet and line wrapping are separate options from the default encoding.
- Text decoding expects the bytes to be valid UTF-8; non-text bytes are reported and can only be saved through the File source.