Turn a Base64 string back into the text it represents. This is the tool you reach for when a log line, a JWT segment, an auth header or a configuration value has arrived encoded and you need to know what it actually says.
The string probably encodes binary rather than text, such as an image or a compressed blob. Base64 carries any bytes, and only some of those are meaningful as text.
JWTs use base64url, a variant that swaps plus and slash for hyphen and underscore and usually drops the padding. Convert those characters back and add equals padding until the length is divisible by four.
No. This matters, because Base64 strings from logs and headers often contain credentials or tokens. Decoding happens entirely in your browser.
Look for a long run of letters, digits, plus and slash characters with no spaces, often ending in one or two equals signs, and a length divisible by four. Authorization headers, JWT segments and data URIs are the places you meet it most often.