Base64URL Converter
Convert between standard Base64 and URL-safe Base64URL.
Make Base64 URL-safe
Standard Base64 uses + and / and = padding, none of which are safe inside a URL. Base64URL swaps them for - and _ and drops the padding, which is why tokens and URL parameters use it. This tool converts between the two.
A value like SGVsbG8/d29ybGQ+ becomes SGVsbG8_d29ybGQ- in URL-safe form. The underlying bytes are identical; only the alphabet and padding differ, so nothing is lost either direction.
Simple and private
It performs a character-level swap and padding fix in your browser, so nothing you paste is uploaded.
Frequently Asked Questions
What is the difference?
Base64URL replaces the + and / characters with - and _ and usually drops the = padding, so the string is safe inside URLs and filenames.
When do I need Base64URL?
In JWTs, URL parameters, and anywhere a Base64 value travels in a link, since + and / have special meaning in URLs.
Does it change the data?
No — only the alphabet and padding change. Decoding either form yields the same bytes.
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