Encodeur et Décodeur Base64

No. Base64 is an encoding, not encryption — anyone can decode it instantly. Never use Base64 to protect passwords or secrets; it only makes binary data safe to transmit as plain text.

The = characters are padding. Base64 encodes data in blocks of 3 bytes into 4 characters, so when the input length is not a multiple of 3, one or two = signs pad the output to a multiple of 4.

Base64 output is about 33% larger than the original, because every 3 bytes of input become 4 characters of output.

Standard Base64 uses + and /, which have special meanings in URLs. URL-safe Base64 replaces them with - and _ so the encoded string can be used directly in query strings and file names.

Yes. Encoding and decoding run entirely in your browser; nothing is sent to a server, so the tool works offline and your data stays private.