UTF-8-safe Base64, processed entirely in your browser — nothing is uploaded.
Decode Base64 to readable JSON online, free. Base64 to JSON decoding reverses Base64 (RFC 4648) back to text, then parses and pretty-prints it as JSON so you can read it. It's the quick way to inspect a JWT claims segment, a data: URI, or any Base64-wrapped JSON payload — decoded entirely in your browser, with nothing uploaded.
It decodes UTF-8-safely and re-indents the result as readable JSON, and tells you when the decoded text isn't valid JSON so you can spot an encoding problem. 100% free, no registration, and complete privacy — everything runs locally in your browser, so your data never touches a server.
Decodes the Base64 and formats the result as readable, indented JSON.
Paste a JWT's claims segment to inspect it; handles UTF-8 content correctly.
Warns when the decoded text isn't valid JSON, so you can tell encoding bugs from non-JSON data.
Tokens, payloads and config never leave your device.
Paste the Base64 string and click Decode. The tool decodes the bytes back to text, then parses and pretty-prints the result as JSON so you can read it. If the decoded text is not valid JSON, it still shows the raw decoded output with a warning.
Usually one of three causes: the string is Base64URL (swap - _ for + /), it is truncated or has wrong padding, or it was never JSON to begin with. The tool reports when the decoded text fails to parse as JSON so you can tell encoding errors from non-JSON data.
Yes — for the claims segment. A JWT has three dot-separated parts; the middle part is Base64URL-encoded JSON. Paste that segment to inspect the claims. Note that JWT uses the URL-safe Base64 alphabet (- and _ instead of + and /); convert those characters if your token does not decode cleanly. For full token parsing, use the JWT Decoder.
No. Decoding, parsing and formatting all run in your browser. Tokens, payloads and config never leave your device.
Yes. The decoder is UTF-8-safe, so accented characters, CJK text and emoji in the original JSON are restored exactly. The output is then re-indented for readability.
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