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Base64 encoder & decoder
Encode text and files as Base64, or decode Base64 into text and files

Library

How Base64 encoding works

Base64 represents each complete three-byte block with four characters from a 64-character alphabet. A shorter final block uses = padding. The format appears in MIME email, data URLs, HTTP Basic authentication, and PEM-style files; JWT uses the related base64url alphabet. For long inputs, the encoded data is about one third larger before line wrapping or other protocol overhead.