Regex Tester
Test regular expressions with live matching and highlighting.
Building response assertions?
Recuro lets you define success assertions on HTTP responses. Validate status codes, headers, and body patterns.
What are regular expressions?
Regular expressions (regex) are patterns that describe sets of strings. They are used for searching, matching, and manipulating text in virtually every programming language. A regex can be as simple as a literal string or as complex as a pattern with quantifiers, character classes, lookaheads, and backreferences.
Common use cases include validating input formats (emails, phone numbers, dates), extracting data from text (log parsing, web scraping), and find-and-replace operations in code editors. Most languages share a similar core regex syntax, though some features vary by engine.
The flags modify how the pattern is applied: g (global) finds all matches instead of
stopping at the first, i makes matching case-insensitive, m (multiline)
makes ^ and $ match at line boundaries, and s (dotAll) makes
. match newline characters.
Building cron URLs that include regex-matched parameters? Recuro handles the scheduling so you can focus on your logic.
Frequently Asked Questions
What regex flavor does this tool use?
This tool uses JavaScript (ECMAScript) regular expressions — the same engine used by browsers and Node.js. Most common regex features like character classes, quantifiers, lookaheads, and named capture groups are supported. Some features from other flavors (like lookbehinds in older browsers or atomic groups) may not be available.
How do I match across multiple lines?
Use the m (multiline) flag to make ^ and $ match at line boundaries instead of just the start and end of the string. Use the s (dotAll) flag to make the dot (.) match newline characters as well. You can toggle both flags using the buttons next to the pattern input.
What are capture groups?
Parentheses in a regex create capture groups. When a match is found, each group captures the portion of text it matched. Groups are numbered starting at 1 — accessible as match[1], match[2], etc. Named groups use the syntax (?<name>...) and are accessible by name. Groups are useful for extracting specific parts of a match.
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