Base64 Encoder & Decoder
Convert text to Base64 and back, including Unicode and URL-safe variants.
Runs entirely in your browser — nothing you paste is sent to our servers.
Base64 is not encryption. It is a fully reversible encoding with no key — anyone can decode it. Use it to carry binary data through a text channel, never to conceal a value.
What this tool does
Full Unicode
UTF-8 encoded first, so Hindi, Japanese, accents and emoji all round-trip. btoa alone throws on these.
URL-safe variant
Swap + and / for - and _ and drop padding — the form JWTs and query parameters use.
Padding tolerance
Decodes input with missing = padding, so a segment copied out of a token just works.
Local only
No request is made, so pasting an encoded credential does not transmit it.
Frequently asked questions
Does this handle emoji and non-English text?
Yes. The text is UTF-8 encoded before being Base64 encoded, so Hindi, Japanese, accented Latin and emoji all round-trip correctly. A naive implementation using btoa alone throws on anything outside Latin-1.
What is URL-safe Base64?
Standard Base64 uses + and / which have meaning in URLs, and = padding which often gets escaped. URL-safe Base64 substitutes - and _ and drops the padding. JWTs use this variant.
Is Base64 encryption?
No, and this matters. Base64 is an encoding, fully reversible by anyone, with no key. It protects nothing. Use it to move binary data through a text channel, never to hide a value.
Why does my decode fail?
Either the input is not valid Base64 (wrong alphabet, or a length that cannot be padded), or it decodes to bytes that are not valid UTF-8 text - which happens when the original data was an image or other binary rather than text.
Do I need to add the padding?
No. If the trailing = characters are missing, this tool restores them before decoding, which is what makes it work on JWT segments copied out of a token.
Monitor it, don't just check it
One-off checks catch what is broken today. CertNotify watches your certificates, domains, DNS and code continuously and tells you before something breaks.