What is the regex for protocol detection?

The regex pattern for protocol detection is `^([a-zA-Z][a-zA-Z0-9+.-]*):\/\/`. This pattern validates detects and captures the protocol from a url.

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /^([a-zA-Z][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'^([a-zA-Z][a-zA-Z0-9+.-]*):\/\/', value)`. The raw string prefix (`r`) prevents Python from interpreting backslashes as escape characters.

Is this regex case-sensitive?

This pattern explicitly handles both uppercase and lowercase via the character classes. No additional flags needed.

Regex for Protocol Detection

Regex Pattern

^([a-zA-Z][a-zA-Z0-9+.-]*):\/\/

Detects and captures the protocol from a URL

Quick Answer

The regex pattern for protocol detection is `^([a-zA-Z][a-zA-Z0-9+.-]*):\/\/`. Detects and captures the protocol from a URL. This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
https://example.com	✓ Matches
ftp://files.example.com	✓ Matches
ws://socket.io	✓ Matches
example.com	✗ No match
://missing	✗ No match
no-protocol	✗ No match

Code Examples

javascript

const regex = /^([a-zA-Z][a-zA-Z0-9+.-]*):\\/\\//;
const isValid = regex.test(value);

python

import re
pattern = r'^([a-zA-Z][a-zA-Z0-9+.-]*):\/\/'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^([a-zA-Z][a-zA-Z0-9+.-]*):\/\//
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^([a-zA-Z][a-zA-Z0-9+.-]*):\\/\\//', $value)) {
    echo "valid";
}

java

String pattern = "^([a-zA-Z][a-zA-Z0-9+.-]*):\\/\\/";
boolean isValid = value.matches(pattern);

Frequently Asked Questions

Related Regex Patterns

Subdomain Extraction

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Port Number

Extracts port number from a URL or host string

Query Parameter

Extracts key-value pairs from URL query strings

HTTP vs HTTPS URL

Matches HTTP or HTTPS URLs and captures the protocol

Data URL

Matches data: URL scheme with optional MIME type and base64 encoding

WebSocket URL

WebSocket URL starting with ws:// or wss://