03 / ENCODE
Base64 & URL Encoder
Encode and decode Base64 or percent-encoded URL strings. UTF-8 safe end to end — text is converted through TextEncoder, so multi-byte characters survive intact.
Why UTF-8 safety matters
The classic btoa("ü") throws, because btoa only understands single-byte characters. This tool encodes text to UTF-8 bytes first, so German umlauts, CJK characters and emoji all round-trip correctly — the same behaviour you get from base64 on the command line.
URL mode uses encodeURIComponent, the strict variant that also escapes &, = and ? — what you want for query-string values. Decoding is fault-checked: malformed input produces an error message, not silent garbage.