Regular Expression (Regex) Tester Guide
Regular Expressions (Regex) are search patterns used to validate, match, and replace characters within text strings. Because regex syntax can be complex and hard to debug (`/^([a-z0-9_\.-]+)@([\da-z\.-]+)\.([a-z\.]{2,6})$/`), developers need interactive tools to test patterns. Our Regex Tester highlights matched text in real time, displays captured group details, and explains pattern components in plain English.
⚙️ Key Features
- Real-time highlighting of regex matches and captured groups as you type.
- Supports standard flags: global (g), case-insensitive (i), multiline (m), and single-line (s).
- Detailed sidebar explanation breaking down the tokens of your regex pattern.
- AI-assisted regex generator to translate natural descriptions into patterns.
📖 How to Use
- Enter your regex pattern in the top input box (excluding the enclosing slashes).
- Paste your target test text into the large text area panel.
- Select the active regex flags (like global or case-insensitive) from the settings list.
- Inspect the highlighted text and review capture group values in the sidebar.
Pattern matching and parsing algorithms run inside your local browser sandbox. No input text or regex patterns are sent over the network.
Frequently Asked Questions (FAQ)
What does the 'global' (g) flag do?
The global flag tells the regex engine to find all matches in the text rather than stopping after the first match. If disabled, only the first match is returned.
How do I match special characters like '.' or '*' literally?
To match regex syntax characters literally, you must escape them using a backslash (e.g. `\.` to match a period, or `\*` to match an asterisk).
What is the difference between lazy and greedy matching?
Greedy quantifiers (like `*` or `+`) match as many characters as possible. Adding a question mark (`*?` or `+?`) makes them lazy, telling the engine to match as few characters as possible.