"Regex looks like hieroglyphics — what do ^, $, .*?, (?=) even mean? Every time I need regex I spend ages searching, and I'm never sure if what I wrote is correct." — regex's learning curve scares away many developers.
Suried Regex Tester provides instant visual feedback — enter your pattern and test text, and matches are highlighted immediately. You can see exactly what your pattern matches and what capture groups capture, learning regex syntax through experimentation.
01 Enter Your First Regex Pattern
Open Suried Regex Tester and you'll see two input areas: the regex pattern input at the top and the test text area below. Enter the simplest regex — a plain string like "hello" — in the pattern field.
Type some text containing "hello" in the test area, and you'll immediately see all matching "hello" instances highlighted. This is the most basic form of regex — literal text matching.
Now try something more interesting: enter "\d+" as the pattern (matches one or more digits), and type "I have 42 apples and 7 oranges" as test text. You'll see "42" and "7" both highlighted — you're already using regex special syntax!
The backslash \ in regex is an escape character. \d means digit, \s means whitespace, \w means word character (letters, digits, underscore). Memorizing these three covers a huge number of use cases.
02 Understanding Flags: g / i / m
Flags control how the regex engine performs matching. Suried Regex Tester provides convenient flag toggle buttons — no manual syntax required.
g (global): Without the g flag, regex stops after the first match. With g, it finds all matches in the text. This is the most commonly used flag — Suried enables it by default.
i (case insensitive): By default, regex is case-sensitive — "Hello" won't match "hello." With the i flag, case differences are ignored.
m (multiline): Affects the behavior of ^ and $. By default, ^ matches only the start of the entire text and $ matches only the end. With m, ^ and $ match the start and end of each line.
03 Viewing Match Results & Highlights
Suried Regex Tester's core strength is instant visualization. As you type your pattern, all matching portions of the test text are immediately color-highlighted. Different matches are distinguished by different colors, so you can see exactly what the pattern matches.
The match info panel displays: total match count, full text of each match, and start/end positions (character indices) in the original text. This information helps you precisely understand regex behavior.
If your pattern doesn't highlight anything, no match was found. Common causes include: syntax errors in the pattern, forgetting to enable the i flag (case mismatch), or the pattern being too restrictive.
04 Using Capture Groups to Extract Data
Capture groups are one of regex's most powerful features. Parts wrapped in parentheses () are captured as a "group," and you can extract the matched content of each group independently.
For example, the date string "2025-01-15" can be matched with (\d{4})-(\d{2})-(\d{2}), where: Group 1 captures "2025" (year), Group 2 captures "01" (month), Group 3 captures "15" (day). Suried Tester clearly displays each group's captured content.
If you want grouping without capturing, use non-capturing groups (?:...). This is useful in complex patterns — logical grouping without affecting group numbering.
Named capture groups (?<name>...) improve readability: (?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2}) is more intuitive than numeric indices.
When using regex in code, capture group indices start from 1 (Group 0 is the full match). Suried Tester's display matches programming language conventions, so you can copy patterns directly into code.
FAQ
Are regular expressions universal across programming languages?
Basic syntax (\d, \w, *, +, ?, [], ()) is universal across most languages. But advanced features (named capture groups, lookbehinds, etc.) may have syntax differences between languages. Suried uses the JavaScript regex engine, perfectly matching web development scenarios.
What's the difference between * and + in regex?
* matches "zero or more" — even if the preceding character doesn't appear at all, it still matches. + matches "one or more" — the preceding character must appear at least once. For example, \d* can match an empty string, while \d+ requires at least one digit.
What's the difference between greedy and lazy matching?
By default, quantifiers (*, +) are greedy — they match as many characters as possible. Adding ? after a quantifier makes it lazy — matching as few characters as possible. For "<b>bold</b>", <.*> matches the entire string, while <.*?> matches "<b>" and "</b>" separately.
Which regex features does Suried Regex Tester support?
Suried Regex uses the browser's native JavaScript RegExp engine, supporting all ES2024 regex features: named capture groups, lookahead/lookbehind assertions, Unicode property escapes (\p{...}), dotAll mode (s flag), and more.
Any general tips for writing regex?
Start simple and refine gradually — don't try to write the perfect regex all at once. Match the most obvious pattern first, then handle edge cases. Use Suried Tester's instant feedback for continuous debugging. Avoid overusing .* (tends to match too much); prefer specific character classes like [\w.-]+.
Try the Tool Now
Suried Regex Tester provides instant visual feedback — enter your pattern and test text, and matches are highlighted immediately. You can see exactly what your pattern matches and what capture groups capture, learning regex syntax through experimentation.