What is the regex for markdown bold?

The regex pattern for markdown bold is `\*\*([^*]+)\*\*|__([^_]+)__`. This pattern validates markdown bold text (**text** or __text__).

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /\*\*([^*]+)\*\*|__([^_]+)__/;` 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'\*\*([^*]+)\*\*|__([^_]+)__', 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 (`/\*\*([^*]+)\*\*|__([^_]+)__/i`) or use `re.IGNORECASE` in Python.

Regex for Markdown Bold

Regex Pattern

\*\*([^*]+)\*\*|__([^_]+)__

Markdown bold text (**text** or __text__)

Quick Answer

The regex pattern for markdown bold is `\*\*([^*]+)\*\*|__([^_]+)__`. Markdown bold text (**text** or __text__). This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
bold text	✓ Matches
__also bold__	✓ Matches
word	✓ Matches
italic	✗ No match
_single_	✗ No match
not bold	✗ No match

Code Examples

javascript

const regex = /\*\*([^*]+)\*\*|__([^_]+)__/;
const isValid = regex.test(value);

python

import re
pattern = r'\*\*([^*]+)\*\*|__([^_]+)__'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /\*\*([^*]+)\*\*|__([^_]+)__/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/\*\*([^*]+)\*\*|__([^_]+)__/', $value)) {
    echo "valid";
}

java

String pattern = "\\*\\*([^*]+)\\*\\*|__([^_]+)__";
boolean isValid = value.matches(pattern);

Frequently Asked Questions

Related Regex Patterns

Markdown Heading

Markdown heading (# to ######)

Markdown Link

Markdown inline link [text](url)

Markdown Image

Markdown inline image ![alt](src)

Markdown Code Block

Markdown fenced code block opening/closing delimiter

camelCase Word

camelCase identifier (starts lowercase, no separators)

snake_case Word

snake_case identifier (lowercase with underscores)