Regex Cheatsheet

How to use it

1. Type a keyword into the search box — try "quantifier", "lookahead" or a symbol like +.
2. The table filters as you type, matching names, descriptions and the pattern column.
3. Click any row to copy the pattern fragment to your clipboard.
4. Group headings (character classes, anchors, flags, and so on) stay visible so you always know which section you are in.
5. Everything is local — there is no regex engine running here, this is a reference, not a tester. For live testing use the Regex Tester tool.

Common use cases

• Writing a pattern from memory — confirm whether it is \d or [:digit:], {2,} or {2,3} before you commit it.
• Reviewing someone else's regex — look up unfamiliar tokens like (?=...) or \b without leaving the tab.
• Teaching or pairing — a shared, searchable reference beats a long blog post during a code review.
• Picking the right flag — check what m, s or u actually change before adding them.

Why it stays private

The reference table is embedded in the page and filtered with plain string operations. Nothing you type is sent anywhere, and there is no analytics on this page.

FAQ

Q: Does this page test my regex? A: No — it is a lookup table only. Use the Regex Tester tool for live matching with highlighting.

Q: Which regex flavor does the table describe? A: JavaScript (ECMAScript) syntax, since every tool on this site runs in the browser. Most tokens are identical in PCRE and Python with minor exceptions noted in the descriptions.

Q: Can I copy more than one entry at a time? A: One click copies one token. Build up your pattern in your editor as you go.