Base64 Encoder / Decoder

Encode or decode Base64 strings — client-side, nothing sent to any server.

Plain Text

Base64 Output

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Encoding vs. encryption

Base64 is not encryption and doesn't hide anything from anyone who bothers to decode it; it's a way to represent binary data as plain text so it survives being passed through systems that only handle text safely, like embedding an image in a data URL, or putting a token in an HTTP header. Anyone can decode a Base64 string in one line of code, in any language.

Where this shows up in Flutter/Dart work

Decoding a JWT's payload (the middle segment of a JWT is Base64Url-encoded JSON), reading a data: URL you copied out of a network request, or checking what's actually inside a Basic Auth header before you commit to debugging further down the stack. Encode and decode both happen instantly, entirely client-side.