What is the regex for basic auth header?

The regex pattern for basic auth header is `^Basic\s+[A-Za-z0-9+/]+=*$`. This pattern validates http basic authorization header (base64 encoded credentials).

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /^Basic\s+[A-Za-z0-9+\/]+=*$/;` and test with `regex.test(yourValue)`. It returns `true` if the value matches.

How do I use this regex in Python?

In Python, use `import re; re.match(r'^Basic\s+[A-Za-z0-9+/]+=*$', value)`. The raw string prefix (`r`) prevents Python from interpreting backslashes as escape characters.

Is this regex case-sensitive?

By default, yes. To make it case-insensitive, add the `i` flag in JavaScript (`/^Basic\s+[A-Za-z0-9+/]+=*$/i`) or use `re.IGNORECASE` in Python.

Regex for Basic Auth Header

Regex Pattern

^Basic\s+[A-Za-z0-9+/]+=*$

HTTP Basic Authorization header (base64 encoded credentials)

Quick Answer

The regex pattern for basic auth header is `^Basic\s+[A-Za-z0-9+/]+=*$`. HTTP Basic Authorization header (base64 encoded credentials). This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
Basic dXNlcjpwYXNz	✓ Matches
Basic YWRtaW46YWRtaW4=	✓ Matches
Bearer token	✗ No match
basic lowercase	✗ No match
Basic	✗ No match

Code Examples

javascript

const regex = /^Basic\s+[A-Za-z0-9+\/]+=*$/;
const isValid = regex.test(value);

python

import re
pattern = r'^Basic\s+[A-Za-z0-9+/]+=*$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^Basic\s+[A-Za-z0-9+/]+=*$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^Basic\s+[A-Za-z0-9+\/]+=*$/', $value)) {
    echo "valid";
}

java

String pattern = "^Basic\\s+[A-Za-z0-9+/]+=*$";
boolean isValid = value.matches(pattern);

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