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// ENCODING · BROWSER

Base64 Encoder/Decoder

Encode text to Base64 or decode it back, UTF-8 safe, with the URL-safe alphabet as an option.

ENCODING · IN YOUR BROWSER

Runs in your browser; nothing you type leaves this page. Too long to share as a link.

HISTORY

Your last 5 runs appear here for 7 days, on this device only.

RESULT

Fill in the form and run the tool; the result appears here.

Base64 Encoder/Decoder converts text to Base64 and back, entirely in your browser. It is an encoding, not encryption: anyone can decode it, so never treat Base64 as a way to protect a secret.

How to read the result

The output box shows the encoded or decoded result. Text is encoded as UTF-8 first, so any character, not only ASCII, round-trips. Decoding invalid input (characters outside the Base64 alphabet, or a length no Base64 string can have) returns an error rather than a corrupted guess; missing = padding is accepted.

Defender tips

  • Treat any Base64 string you find in a config file, repository or mobile app as plaintext for the purpose of a security review; decoding it takes seconds.
  • If you need confidentiality, encrypt first and encode the ciphertext, do not encode alone and call it protected.
  • Watch for Base64 used to smuggle payloads past naive input filters that only pattern-match on plain text.

FAQ

Does it support the URL-safe variant?

Yes. Standard Base64 uses + and /; the URL-safe variant uses - and _ instead, so the output can sit in a URL without further encoding. Tick "URL-safe alphabet" to encode that way (without padding); decoding recognises either alphabet on its own.

Why does decoding sometimes fail?

Either the input is not valid Base64 (a character outside A-Z, a-z, 0-9, + and / or their URL-safe equivalents, or an impossible length), or it decodes to bytes that are not UTF-8 text, such as an image or other binary data, which this text tool cannot display.

Is this the same as encryption?

No. Base64 has no key and no secret; it is purely a way to represent binary data as text, fully reversible by anyone.