Regex Cheatsheet

Search regular expression tokens, examples, flags, groups, and copy-ready recipes

Regex Cheatsheet

Search common regular expression tokens, examples, flags, and recipes.

Character Classes

Match individual characters or character families.

10 entries

TokenMeaningExampleCopy

.

Any character except newline

a.c matches abc

\d

Digit, same as [0-9]

\d{3} matches 123

\D

Not a digit

\D+ matches abc

\w

Word character, [A-Za-z0-9_]

\w+ matches user_1

\W

Not a word character

\W matches !

\s

Whitespace

a\sb matches a b

\S

Not whitespace

\S+ matches text

[abc]

One character from the set

gr[ae]y matches gray

[^abc]

One character not in the set

[^0-9] rejects digits

[a-z]

Character range

[a-z]+ matches slug

Anchors

Pin matches to positions in the input.

4 entries

TokenMeaningExampleCopy

^

Start of string or line

^Hello

$

End of string or line

done$

\b

Word boundary

\bcat\b

\B

Not a word boundary

\Bcat\B

Quantifiers

Control how many times the previous token may repeat.

7 entries

TokenMeaningExampleCopy

*

Zero or more

ab*c

+

One or more

ab+c

?

Zero or one

https?://

{3}

Exactly 3

\d{3}

{2,5}

Between 2 and 5

\w{2,5}

{2,}

At least 2

\d{2,}

*?

Lazy zero or more

<.*?>

Groups and Alternation

Combine tokens, capture text, and choose alternatives.

5 entries

TokenMeaningExampleCopy

(abc)

Capturing group

(\d{4})-(\d{2})

(?:abc)

Non-capturing group

(?:com|org|net)

(?<name>abc)

Named capture group

(?<year>\d{4})

|

Alternation / OR

cat|dog

\1

Backreference to group 1

(\w+) \1

Lookarounds

Assert nearby text without consuming it.

4 entries

TokenMeaningExampleCopy

(?=abc)

Positive lookahead

\d(?=px)

(?!abc)

Negative lookahead

\d(?!px)

(?<=abc)

Positive lookbehind

(?<=#)[A-Fa-f0-9]+

(?<!abc)

Negative lookbehind

(?<!-)\d+

Flags

Change how the regex engine searches.

6 entries

TokenMeaningExampleCopy

g

Global search

/cat/g

i

Case-insensitive

/devfox/i

m

Multi-line anchors

/^title/gm

s

Dot matches newline

/<div>.*<\/div>/s

u

Unicode mode

/\p{L}+/u

y

Sticky match

/\d/y

Common Recipes

Copy-ready starting points for frequent patterns.

6 entries

TokenMeaningExampleCopy

^[\w.-]+@[\w.-]+\.\w{2,}$

Simple email

[email protected]

^https?:\/\/.+$

HTTP or HTTPS URL

https://devfox.dev

^#?(?:[A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})$

Hex color

#22c55e

^\d{4}-\d{2}-\d{2}$

YYYY-MM-DD date

2026-05-19

^[a-z0-9]+(?:-[a-z0-9]+)*$

URL slug

regex-cheatsheet

^\+?[1-9]\d{1,14}$

E.164 phone number

+14155550199

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What is Regex Cheatsheet

Written by Giorgos Kostas. Last reviewed: April 18, 2026

A regular expression (regex) is a concise pattern language for matching and extracting parts of text, supported across virtually every programming language.

Regex Cheatsheet is an online tool that helps you search regular expression tokens, examples, flags, groups, and copy-ready recipes.

Use it when you need to process regex Cheatsheet quickly and keep the input, output, and controls in the same browser tab.

Why use it

Use regex Cheatsheet directly in the browser without extra setup.
Speed up repetitive regex Cheatsheet tasks with copy-ready output.
Reduce avoidable manual mistakes when working with regex Cheatsheet.
Keep regex Cheatsheet work focused in one page instead of juggling multiple tools.

Example (before/after)

Regex Cheatsheet input

Start with the regex Cheatsheet input you want to process in Regex Cheatsheet.

Regex Cheatsheet output

Get a regex Cheatsheet result from Regex Cheatsheet that is ready to review, copy, and reuse in the next step of your workflow.

Common errors

Unsupported input

The tool may reject input that does not match the expected content, structure, or file type.

Fix: Confirm the tool input requirements and paste the correct type of data.

Incomplete values

Missing fields or partial content can block processing or produce weak results.

Fix: Provide the full required input before running the tool.

Copying placeholder content

Sample or placeholder values can lead to output that looks valid but is not ready for real use.

Fix: Replace placeholders with your actual values before relying on the result.

FAQ

Does Regex Cheatsheet highlight matches in real time?

Yes. Matches are highlighted as you type, and the match count plus capture groups update on every keystroke. For very long inputs, highlighting is debounced to keep typing responsive.

What diff algorithm does Regex Cheatsheet use?

Regex Cheatsheet uses the same Myers diff algorithm that git uses under the hood, so the output lines up with what you'd see in a git diff. Line-level and character-level modes are both available.

Can I save sessions in Regex Cheatsheet?

Inputs are persisted to your browser's local storage between reloads — you can close the tab and come back to the same regex or input later. The data stays on your device.

Does Regex Cheatsheet support multi-line mode and flags?

Yes. All standard JavaScript regex flags — g, i, m, s, u, y — are exposed as checkboxes in the UI, and the flag string is included when you copy the pattern.

Can I export matches from Regex Cheatsheet?

Matches can be exported as JSON (one object per match with index, value, and capture groups), CSV, or a raw list. The export respects the current flags and input.

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