Basic Auth Header Generator
HTTP Basic authentication sends credentials as Base64 in the Authorization header. This tool builds the correct header value from a username and password, and generates ready-to-use curl, fetch, and Python snippets.
Basic auth is just Base64 over user:password, so the Base64 Encoder shows the same bytes. For modern tokens see the JWT Verifier, and for server config the htpasswd Generator.
How to use the Basic Auth Header
- 1 Enter the username and password.
- 2 Copy the generated Authorization header value.
- 3 Add it to your request as an Authorization header with the Basic scheme.
- 4 Make sure the request goes over HTTPS.
How to Use
Enter the username and password, then copy the header value or one of the generated snippets. Encoding happens locally in your browser.
- Builds the exact Authorization header value
- Correct UTF-8 Base64 encoding
- Ready-made curl, fetch, and Python examples
- Manual Base64 encode and decode
- Credential encoding is done on your device
Frequently asked questions
Is a Basic auth header secure?
Only inside TLS. The credentials are Base64-encoded, which is trivially reversible — anyone who can see the request can read the password in seconds. Over HTTPS the header is protected by the transport, but on plain HTTP it is effectively public.
What does the header actually contain?
The word Basic, a space, then the Base64 of username:password joined by a colon. The colon matters: a username containing one will break the parse, which is why Basic auth disallows colons in usernames.
Why does my browser show a login popup?
Because the server replied with a 401 and a WWW-Authenticate header asking for Basic credentials. The browser handles the prompt and then resends the request with the header already attached, which is why you never see it in the URL.
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