Yes. This is where most online Base64 encoders break: the browser's built-in btoa() throws an error on any character above U+00FF, so it fails on the first emoji, accented letter or CJK character. This tool encodes the text to UTF-8 bytes first, so any Unicode input works correctly.
Is Base64 encryption?
No, and this matters. Base64 is an encoding, not a cipher — anyone can decode it instantly with no key. It exists to carry binary data through text-only channels, not to hide anything. Never use it to protect a password, token or personal data.
When should I use the URL-safe alphabet?
When the result goes into a URL path, query string or filename. Standard Base64 uses + and /, which have reserved meanings in URLs and would need percent-encoding. base64url (RFC 4648 §5) substitutes - and _ and drops the = padding. JWTs use it for exactly this reason.