Base64 Decoder
What is Base64 Decoder
Base64 decoding converts a Base64-encoded string back into its original text or binary representation. This tool accepts any valid Base64 string and outputs the decoded text instantly — no server involved, everything runs in your browser.
How to use
- Paste the Base64 string into the input field.
- The decoded text appears instantly in the output area.
- Click Copy to copy the decoded result to your clipboard.
- Use the Base64 Encoder link below to go the other direction.
Use cases
A developer receives a Base64-encoded JWT token payload from an API response. They paste the payload segment into this decoder to inspect the JSON claims — such as user ID, roles, and expiry time — without writing any code.
Frequently asked questions
What is Base64 decoding?
Base64 decoding reverses the Base64 encoding process, converting a Base64 string back to the original text or binary data. It is a standard operation supported in all programming languages.
What happens if I enter an invalid Base64 string?
The decoder shows an error message instantly. Common causes are missing padding characters (=), invalid characters, or whitespace inside the string.
Can I decode Base64 data URLs?
Yes. Paste the part after the comma in a data URL (e.g. the content after 'data:image/png;base64,') and the decoder will output the binary representation as text.
Is this decoder safe to use with sensitive data?
Yes. All decoding happens locally in your browser using JavaScript. No data is ever sent to any server.
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