Base64 exists because plenty of transports — email headers, JSON strings, data URIs, HTTP basic auth — only reliably carry printable ASCII. It encodes arbitrary bytes into 64 safe characters at a cost of about 33% extra size. This tool converts in both directions and handles Unicode correctly.
No, and treating it as such is a genuine security mistake. It is a reversible encoding with no key. Anyone can decode it instantly, so never use it to hide a secret.
A variant that replaces + with - and / with _, because the standard characters have reserved meanings in URLs. JWTs use this variant, which is why they contain no plus or slash characters.
Because it packs three bytes into four characters, adding roughly one third. The = padding at the end aligns the output to a multiple of four characters.
Naive implementations call btoa directly, which only handles Latin-1. This tool encodes to UTF-8 bytes first, so emoji and non-Latin scripts round-trip correctly.
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