Convert text to Base64 and back. UTF-8 safe — works with Chinese, emoji, and any characters. Everything runs locally in your browser.
No. Encoding and decoding run entirely in your browser as JavaScript — nothing is uploaded, logged, or stored. Once the page has loaded it keeps working even if you go offline.
No. Base64 is an encoding, not encryption, and anyone can reverse it without a key. It is useful for making data safe to carry as text, but never rely on it to hide a secret.
The decoder expects standard Base64: A–Z, a–z, 0–9, + and / with = padding. URL-safe variants use - and _ instead, so JWT segments should go to the JWT Decoder, which converts Base64URL automatically.