Regex

Test and debug regular expressions across PCRE, JavaScript, and Python flavors. See matches highlighted, capture groups extracted, and quantifier behavior explained.

All Regex

• Regex Tester Test regular expressions against text. PCRE, JavaScript, and Python flavors.
• Regex Explainer Break down a regex into plain English. Explains each token, group, quantifier.
• Regex Cheatsheet Searchable reference of regex syntax: classes, quantifiers, lookarounds, flags.
• Regex from Examples Paste examples of strings to match; get a regex that matches them all.
• Regex Replace Tester (Live, with Capture Groups) Test regex find + replace with capture group references ($1, $&). Live preview, all flags.
• Regex Visualizer (Railroad Diagram) Render any regex as a railroad diagram. See alternations, character classes, quantifiers at a glance.
• Common Regex Library (Email, URL, IP, Phone, Date) Searchable library of validated regex patterns: email, URL, IPv4 / IPv6, phone, ZIP, hex color, ISBN, credit card. Copy with one click.
• Regex Flags Reference (i, g, m, s, u, y, x) What every regex flag does, side-by-side. JavaScript, Python, Perl, PCRE — differences highlighted.
• Regex Backreference Tester Test backreferences (\1, \k<name>) live. Helps debug palindrome / duplicate-word / matched-tag regexes.
• Build Regex from Example Strings Paste 2-20 example strings; get a regex that matches all of them (and only the patterns you intend). Generic→specific dial.
• Regex Anchors Tester (^, $, \b, \B) Test regex anchors interactively. See where ^, $, \b, \B match in your input. Multiline / single-line behavior.
• Regex Cheat Sheet by Language (JS, Python, PHP, Java, Go) Side-by-side regex syntax reference. Anchors, quantifiers, lookbehinds, named groups — how each language varies.
• Regex Character Class Builder ([abc], [a-z], [^...]) Visually build character classes. Pick ranges, individual chars, negation. Output the regex syntax.
• Regex Escape / Unescape Tool Escape special characters in a string so it works as a literal inside a regular expression. Unescape too.
• Regex String Generator (Reverse Regex) Generate example strings that match a regular expression — great for test data and understanding a pattern.
• Glob to Regex Converter Convert glob patterns (*.js, src/**/*.ts) into equivalent regular expressions. Bash and minimatch styles.
• Regex Lookahead & Lookbehind Tester Test regex lookahead and lookbehind assertions live. See what matches without the assertion being consumed.
• Regex Match Extractor Extract every match of a regex from text as a clean list. Pull emails, URLs, numbers, or any pattern out of logs.
• Regex Split Tester See how a regular expression splits a string into parts, just like String.split with a pattern.
• Regex Named Group Extractor Run a regex with named capture groups over text and extract each match as a JSON object and table.
• Regex Match Counter Count how many times a regex matches, list each match with its position, and tally distinct values.
• Word List to Regex Turn a list of words into one regex that matches any of them, with escaping and trie optimization.
• Regex Extract Matches Extract every regex match or a chosen capture group into a clean list, with optional dedupe, sort, and join.
• Regex Escape & Unescape Escape a literal string for safe use inside a regular expression, or unescape one back to plain text.
• Regex Line Filter — Browser grep Filter lines by a regex: keep matches, invert, show line numbers, or print only the matched part.
• Route Pattern to Regex Converter Convert route patterns like /users/:id and /posts/{slug} into a regex with capture groups, plus a live path tester.
• Regex Unicode Property Escapes Reference Reference for regex Unicode property escapes like \p{L} and \p{Script=Greek}, with a live match-highlighting tester.
• Regex Quantifier Reference & Demo Reference for regex quantifiers and greedy versus lazy matching, with a live demo that highlights matches.