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Basic Auth Header

Build Authorization Headers — computed locally in your browser.

Build an Authorization header

Base64 value:
Header line
Basic authentication sends the password on every request, so it is safe only over HTTPS.

How to use the Basic Auth Header

  1. Type the username and the password you want to encode.
  2. Press build to see the Base64 value and the full header line.
  3. Copy the header and send it only over an HTTPS connection.

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Frequently Asked Questions

Common questions about the free online basic auth header.

It is the word Basic, a space and then the Base64 encoding of the username, a colon and the password.
Only over HTTPS. The password travels in every request, so without TLS anyone on the path can read it.
Yes. Base64 is an encoding and not encryption, so anyone who sees the header can recover the username and password.
The value is encoded as UTF-8 before Base64, which matches the modern behaviour of browsers and servers.
It is acceptable for internal tools behind TLS, and better when combined with a token or an application password.
Use the user option with your username and password, which makes curl build exactly this header for you.
No. The same credentials always produce the same header, which is one reason to prefer short lived tokens instead.
Headers are often logged in full, so treat any request log as sensitive when Basic authentication is in use.
A colon with an empty password is legal, but most servers reject it, and it is only sensible for anonymous test accounts.

Last updated: October 10, 2026