Builds an HTTP Basic Authorization header.
The Basic Auth Header tool builds an HTTP Basic Authorization header from a username and password. It joins them as username:password, UTF-8 encodes the result, base64-encodes it, and returns a ready-to-use Authorization: Basic <token> line. This is handy whenever you need to authenticate an HTTP request that uses Basic auth, such as testing an API with curl, Postman, or a browser fetch.
No. The encoding runs entirely in your browser using TextEncoder and btoa, and nothing you type is uploaded or logged. The username and password never leave your device.
It outputs a full header line in the form Authorization: Basic <token>, where <token> is the base64 encoding of username:password. You can paste the whole line into a request or use just the token after Basic.
The username is trimmed of surrounding whitespace, then joined with the password using a single colon as username:password before encoding. The password is taken as-is and is not trimmed.
Yes. The credentials are encoded as UTF-8 bytes before base64 encoding, so characters outside the ASCII range are handled correctly.
No. Base64 is reversible encoding, not encryption, so anyone who sees the header can decode the credentials. Always send Basic auth over HTTPS to keep them protected in transit.