JWT Decoder
Inspect the header and payload of a compact JWT without verifying its signature.
Open toolBase64 Encode Decode
Encode Unicode text into standard Base64 or decode padded Base64 back to UTF-8 text. Choose a direction, inspect the output and copy the converted text.
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Enter the inputs, then select Calculate.
Your result
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How Base64 Encode Decode works
The encoder converts UTF-8 text bytes to standard Base64, while the decoder validates the padded representation and requires valid UTF-8 output.
Whitespace around Base64 can be ignored during decoding, but Base64url is a different alphabet. This changes a representation and provides no encryption.
The field is limited to 100000 characters.
How to use Base64 Encode Decode
Choose encode or decode and use text in the supported standard Base64 format.
Choose text or encoded input
Select Encode or Decode and enter the source text or standard Base64. Encoding expects Unicode text. Decoding expects canonical standard Base64 with the required padding, not JWT-style Base64url.
Text or Base64
Run the representation change
Run the conversion and inspect the Encoded or Decoded result. Its character total describes the generated output, while the main text panel contains the value to review.
Decoded
Copy and check the output type
Copy the output after checking the direction. Read the encoding note: this is not encryption. A decoding failure can mean invalid padding or bytes that are not UTF-8 text, rather than a lost password.
Output and export
When to encode or decode Base64 text
Use the result to inspect a text representation, not to protect a secret.
Inspect an encoded text field
Decode a field documented as standard Base64 text to read its contents. Keep the source field name and encoding convention with your notes. If the field holds binary data instead, a decoding error does not establish that the original data is corrupt.
Encode UTF-8 text for a test fixture
Encode a small known message for an integration fixture that explicitly expects UTF-8 text in Base64. Use the destination requirements to choose the representation. Encoding here does not create a file upload, sign a message, or send a request.
Compare a round trip
Encode text and decode the resulting string to inspect whether the characters survive the round trip. Include meaningful nonASCII characters and line breaks in the sample. This checks the chosen text representation rather than the behavior of a separate application.
Separate encoding from encryption
Treat Base64 as a text representation of bytes when deciding where the result belongs.
Base64 changes the representation of bytes; it does not conceal the content from someone who can decode it. Do not use the encoded result as a password protection or encryption mechanism.
The decoder requires valid padding and valid UTF-8. It rejects malformed sequences rather than substituting replacement characters, which helps avoid silently changing a text payload.
Check standard Base64 padding and UTF-8 errors
Choose the direction that matches your source and keep meaningful whitespace when it forms part of the text.
The field is limited to 100000 characters. Empty input is rejected, although whitespace itself can be meaningful text when encoding. Confirm the selected direction before interpreting a failed conversion.
If a token uses Base64URL or lacks standard padding, inspect its documented format instead of editing characters at random. Use the JWT decoder for a compact token with separate encoded segments.
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Open toolEncode or decode standard Base64 text
Choose encode or decode and use text in the supported standard Base64 format.
Base64 Encode Decode: common questions
Answers about using Base64 Encode Decode and understanding its results.
Does it support non-English text?
Yes. Unicode text is UTF-8 encoded before Base64 conversion.
Why was decoding rejected?
The input must be canonical padded standard Base64 and decode to valid UTF-8.
Can I decode arbitrary binary files?
This form returns Unicode text and rejects bytes that are not valid UTF-8. It is not a binary-file converter.
Is Base64url accepted?
No. Use canonical padded standard Base64 here. JWTs use their own Base64url segment representation.