A reference you can actually keep
Most regex cheat sheets are one-size-fits-all — a wall of every token you might ever need, whether you're working with lookaround or not. This one lets you pick the sections that matter for what you're doing, filter down to a specific token or keyword, and export exactly that as Markdown, plain text, or a downloadable .md file to keep in your notes or drop into a team wiki.
The reference covers character classes, anchors, quantifiers, groups and backreferences, lookaround, flags, escaping, and a handful of ready-made patterns for things like email addresses and IPv4 addresses — all JavaScript RegExp syntax, matching the engine every other regex tool on this site uses.
Pairing it with the other regex tools
Once you've got the syntax down, the Regex Builder lets you assemble a pattern by clicking instead of typing it from memory, the Regex Tester runs a pattern against sample text with live match highlighting, and the Regex Visualizer breaks an existing pattern down into a diagram so you can see its structure at a glance. If a pattern isn't behaving the way you expect, the Regex Debugger steps through a match attempt piece by piece.
FAQ
Does this cover other regex flavors, like PCRE or Python's re?
No — this reference (and every regex tool on this site) is specifically JavaScript RegExp syntax. Most of it overlaps heavily with other flavors, but details like lookbehind support and flag letters vary between languages.
Does the filter affect what gets exported?
No — the filter only narrows what's shown on this page so you can find a token quickly. Copying or downloading always exports the full content of whichever sections are checked above, regardless of the current filter text.