Web tools

The Web Tools category has a Regex Tester, an HTTP Status Codes reference and a URL Parser.

Regex Tester

A regular expression (regex) is a pattern that describes text, such as "four digits, a dash, two digits". The tester shows what a pattern matches while you type it.

1. Open Regex Tester and type the pattern in Pattern. Do not add slashes around it. The / shown in the field is decoration.

2. Type or paste the text to search in Test text.

3. Read the result below. It updates on every keystroke:

   • A count, such as 3 matches, or No matches.
   • Your test text with every match highlighted.
   • One card per match: its number, the matched text, where it starts and ends (index 5–12) and the values of its capture groups, if the pattern has any.

Three options change how the pattern is applied:

Option	Default	What it does
Case sensitive	On	Turn off to let a match A.
Multiline (^$ per line)	Off	Makes ^ and $ match at the start and end of every line, not only of the whole text.
Dot matches newline	Off	Lets . match line breaks too.

A worked example: enter the pattern (\d{4})-(\d{2}) and the test text From 2026-07 to 2026-11. The tester reports 2 matches. The first card shows 2026-07, index 5–12 and groups: 2026, 07.

If the pattern is not valid, for example an opening bracket with no closing one, a card shows the error instead of the results.

Good to know

The match list shows the first 100 matches. The count and the highlighting cover all of them. The pattern syntax is the one used by JavaScript, so a pattern that works here works in a browser or in Node.js.

HTTP Status Codes

A searchable list of the status codes a web server returns, from 100 to 504, each with its name and a one-line meaning. To learn what status codes are, read HTTP basics.

1. Open HTTP Status Codes.

2. Type in Search by code or name…. You can search by number (404), by name (gateway) or by a word in the description (redirect).

3. Scroll the list to read the matches.

The circle next to each code is coloured by its class:

Codes	Class	Colour
1xx	Informational	Grey-blue
2xx	Success	Green
3xx	Redirection	Blue
4xx	Client error	Orange
5xx	Server error	Red

The list covers the 32 codes you are most likely to meet. It is not the complete registry.

URL Parser

Splits a URL into its parts, so you can see exactly which host, path and parameters a link contains.

1. Open URL Parser and paste a URL into URL.

2. Read the parts in the card below. It updates as you type.

3. Select the copy icon on any row to copy that value.

For https://user@example.com:8080/path?a=1&b=2#section the tool shows:

Row	Value
Scheme	https
Host	example.com
Port	8080
User info	user
Path	/path
Query	a=1&b=2
Fragment	section

Below that, Query parameters lists each parameter with its decoded value: a is 1, b is 2. A parameter that appears twice is listed twice.

Port, User info, Query and Fragment appear only when the URL has them. A part that exists but has no value shows (empty).

Next steps

• Text tools for URL Encode / Decode
• Design tools
• HTTP basics