Loading Base64 Decoder
Also available in the Chrome extension Every Zase tool also lives in the free Developer Toolkit by Zase extension: fully offline, in a window or the side panel, one keyboard shortcut away.
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About this Base64 Decoder
Base64 strings turn up everywhere: auth headers, JWT segments, email bodies, API payloads and config values. This decoder turns them back into readable text with correct UTF-8 handling, entirely in your browser. That local part matters: the string you are decoding is often a credential or a token, and it should not be pasted into a stranger's server just to be read.
How to use the Base64 Decoder
- Paste the Base64 string into the input panel (a sample is loaded).
- Click Decode.
- Read or copy the decoded text.
Good to know
- UTF-8 aware: multilingual text decodes back exactly as it was encoded.
- Invalid input is reported clearly instead of returning garbage.
- Decoding is fully local: tokens and credentials never leave your device.
Frequently asked questions
Why did my string fail to decode?
Usually it was truncated in copying, includes a space or newline in the middle, or is Base64URL (with - and _ characters) rather than standard Base64. Check the full string, including any = padding at the end.
Can this decode the parts of a JWT?
JWT segments use the Base64URL variant. For tokens, use the JWT Decoder on this site, which handles that variant and labels the header and payload for you.
Is it safe to decode an API key or token here?
Yes. Decoding runs locally in your browser tab; nothing is uploaded, stored or logged. The string stays on your device from start to finish.