When you'll need this
- Reading Basic auth headers (
Authorization: Basic …) or SAML assertions while debugging SSO. - Decoding Base64URL segments of JWTs. Our JWT decoder does this automatically.
- Unpacking percent-encoded redirect URLs from HAR files to see where a login flow is actually sending the browser.
Frequently asked questions
What's the difference between Base64 and Base64URL?
Base64URL replaces + with - and / with _, and usually drops the = padding, so the result is safe inside URLs and filenames. JWTs use Base64URL.
Why does my decoded text look garbled?
The original data was probably binary (an image or compressed data) or used a different character encoding. This tool decodes as UTF-8.
Should I use encodeURI or encodeURIComponent?
Use component encoding (what this tool does) for individual query parameter values. It escapes characters like &, = and / that would otherwise change the meaning of the URL.
Is Base64 encryption?
No. Base64 is an encoding that anyone can reverse. Never use it to protect secrets.