Base64 & URL codec.
Type in either box and the other updates. UTF-8 safe. Nothing leaves your browser.
About this tool
Base64 turns arbitrary bytes into a safe ASCII alphabet and is what you will find in Authorization: Basic headers, data URIs and many config files. Base64url swaps + and / for - and _ and drops the padding, and is used in JWTs and anywhere the value has to survive inside a URL. Percent-encoding escapes characters that are not allowed in a URL; the "component" variant also escapes /, ? and & so a value can be dropped into a query string without changing its meaning.
Text is treated as UTF-8 in both directions, so emoji and non-Latin scripts round-trip correctly. Whitespace in Base64 input is ignored, which makes pasting wrapped output from openssl or email painless.