Base64URL Encoder, Decoder and Converter
Base64URL replaces + with - and / with _ and usually drops the = padding, so the text is safe in web addresses, cookies and file names. Use this page to encode text as Base64URL, decode it, or convert existing Base64 between the two alphabets.
How to use the Base64URL tool
- Choose what you want: encode text, decode Base64URL, or convert Base64 <-> Base64URL.
- Paste your input.
- Copy the result.
Questions and answers
Where is Base64URL used?
In JSON Web Tokens (JWT), OAuth PKCE codes, WebAuthn, URL parameters, and anywhere a value must not contain + / or =.
Is the padding needed?
Base64URL usually omits it (JWT forbids it). The decoder here works with and without padding.
Can a normal Base64 decoder read Base64URL?
Not always: strict decoders reject - and _. Convert it to standard Base64 here first.
Is my data uploaded to a server?
No. Every conversion on this page runs inside your browser with JavaScript. Your text and files never leave your computer, which is why it also works for private keys, contracts and photos.
Is the tool free?
Yes, free without sign-up and without limits other than your computer's memory. The site is paid for by the small ads on the left and at the bottom.