Base64 encode/decode · Guide
Common Base64 Mistakes
Base64 looks foolproof, but a few recurring mistakes cause most decoding failures. Here is what to watch for.
Confusing Base64 and Base64url
Base64url replaces + and / with - and _ so the string is safe in URLs and filenames. Decoding Base64url with a standard decoder fails. JWTs, for example, use Base64url.
Missing or wrong padding
Standard Base64 pads with = to a length that is a multiple of four. Strings with the padding stripped need it restored before some decoders accept them.
Treating it as security
Base64 is encoding, not encryption. Putting a password in Base64 hides nothing — it is trivially reversible. Use real cryptography for secrets.
Frequently asked questions
Can I use this for production work?
Yes, for inspection, formatting and quick generation. Still review the output before committing it to production code or configuration.
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