Regular Expressions 101

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Community Patterns

Search among community submitted regex patterns...

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1

TA_P1

Created·2026-03-26 09:45

Flavor·PCRE2 (PHP)

Submitted by anonymous

1

plfjahr42

Created·2026-03-25 07:21

Flavor·PCRE2 (PHP)

plf HIIILLFFEEE

Submitted by Lecksie Hartman

1

plfJahr4

Created·2026-03-25 07:14

Flavor·PCRE2 (PHP)

Submitted by Lecksie Hartman

1

Murat67

Created·2026-03-24 22:53

Flavor·PCRE2 (PHP)

Submitted by webler4000

1

wald493#2

Created·2026-03-24 20:24

Flavor·PCRE2 (PHP)

Wer den Löwen weckt muss auch mit ihm tanzen!

Submitted by Webler3000

1

Capture group finder

Created·2026-03-23 19:06

Flavor·PCRE2 (PHP)

A regex to inspect other regex and match all capture groups

Submitted by SP4CEBAR

1

translation batch name structure

Created·2026-03-16 13:15

Flavor·PCRE2 (PHP)

internal structure of a batch name

Submitted by msoutopico

2

Almost universal anime filename matcher

Created·2026-03-07 18:37

matches anime filenames. such as Group] Name [Episode[Audiometa]others.ext supports NCOP, NCED, OP, ED, SP, SPnn, nn, nn.n, nn.n_vn mp4, mkv, srt, ass but you could add more. the episode must be written within a [] bracket. finally, this regex cannot cover all the cases and obviously have some issues, but it's fine under most cases. it is also a small regex practice for me.

Submitted by NullCompute0754

2

GHAS Custom Secret Scanning Regex for Password/Secret/API Key (Excludes ${...} and process.env)

Created·2026-03-06 15:52

Flavor·PCRE2 (PHP)

This is a GitHub Advanced Security (GHAS) Secret Scanning Custom Pattern I created to detect likely hardcoded credentials while reducing common false positives in code. Goal: detect assignments for these key names: password secret apikey / api_key / api-key Pattern regex: (?i)\b(password|secret|api[-]?key)\b\s[:=]\s(?!\s\$\{)(?!\sprocess\.env\b)(?:['"])?[A-Za-z0-9!@#$%^&()+=-]{5,}(?:['"])? What it should catch (examples): password: "ahsjdfahsjfhdjsahj" secret = 'kjfskahfsdhfj' apikey: ABCDE12345!@# (unquoted) What it tries NOT to catch (common false positives): password: ${password_somename} (template/variable placeholder) secret: ${VAULT_SECRET} password: process.env.DB_PASSWORD (env var reference, not a hardcoded secret) This is intended as a practical baseline; it won’t be perfect for every language/config style. If you have suggestions to improve the detection accuracy (reduce false positives/false negatives) for GHAS custom patterns, please share.

Submitted by GearoidMaguire

1

Flatten 1 line CSS

Created·2026-03-01 16:22

Updated·2026-03-01 17:35

Flavor·PCRE2 (PHP)

Finds CSS selectors that only contain one line and, using the substitution, flattens everything to be on the same line.

Submitted by anonymous

1

IP address

Created·2026-03-01 02:22

Flavor·PCRE2 (PHP)

Matches and verifies IP address. 192.168.0.1 Matches 999.999.9.9 Didn't match

Submitted by anonymous

1

Validate an IP

Created·2026-02-25 11:06

Updated·2026-02-25 11:11

Flavor·PCRE2 (PHP)

52 character long regex to validate IP address.

Submitted by Karthik

1

number selector, with commas & decimals

Created·2026-02-12 05:04

Flavor·PCRE2 (PHP)

selects numbers, with commas and decimals, like 1,234.56

Submitted by Bicorn

1

Smart outer parentheses selector with backslash escaping

Created·2026-02-10 03:26

Updated·2026-02-12 01:11

Flavor·PCRE2 (PHP)

Grabs the outer parentheses and contents taking into account inner parentheses enclosures

Submitted by bicorn

1

nexus/sonartype composer cleanup of unfinished package versions

Created·2026-02-05 13:05

Flavor·PCRE2 (PHP)

matches composer packages with -alpha, -beta and -rc versionings

Submitted by Anna Damm

1

OmegaT Project Name (Pattern)

Created·2026-02-03 16:49

Flavor·PCRE2 (PHP)

Regex showing how to match the five parts in an OmegaT project name (named as per the internal convention at cApStAn), including labels for each captured group (each part in the name).

Submitted by msoutopico

2

Validate color with grb group

Created·2026-02-03 03:22

Updated·2026-02-04 03:36

match: #aabbcc #abc (255,255,255) (255,255,255,255) 255,255,255 no match: #gggggg #ggg 256,256,256

Submitted by Doyoung

1

unnecessary closing HTML tags

Created·2026-01-27 19:15

Flavor·PCRE2 (PHP)

Selects the ` and ` tags from a string. You can probably do this with something easier, but this works

Submitted by Twineee

1

Door_Double

Created·2026-01-27 07:54

Updated·2026-01-28 10:27

Regex for Door_Double

Submitted by anonymous

1

ตรวจสอบพยัญชนะต้นตัวสะกดสระและวรรณยุกต์ไทย

Created·2026-01-22 01:36

Updated·2026-01-23 12:42

Flavor·ECMAScript (JavaScript)

ตรวจสอบพยัญชนะต้น (ต้องมี) ตรวจตัวสะกดสำหรับสระที่ต้องมี ตรวจสอบการวางสระและวรรณยุกต์ไทย หมายเหตุ การตรวจสอบตัวสะกดในภาษาไทยตรวจสอบได้ยากเพราะภาษาไทยเป็นภาษาที่เขียนติด ๆ กันไม่มีการแบ่งคำอย่างชัดเจนทำให้การอ่านภาษาไทยผู้อ่านต้องใช้ความหมายของคำในการตัดสินการอ่านแบ่งคำตามความเหมาะสมเช่นคำว่า "ตากลม" อาจอ่านเป็น "ตาก-ลม" ก็ได้ หรืออ่านเป็น "ตา-กลม"ก็ได้ ดังนั้นการเขียน Regex เพื่อทำการตรวจสอบอาจช่วยได้ระดับหนึ่ง อ่าจมีผิดบ้างถูกบ้าง แต่ก็ถือว่าเป็นเครื่องมือที่ใช้ช่วยเหลือในการตรวจสอบเพิ่มเติมได้ 80% ของความเป็นไปใด้ก็แล้วกันนะครับ หวังว่าการเขียนเพิ่มเติมส่วนนี้ จะมีประโยชน์บ้างไม่มากก็น้อย

Submitted by อธิปัตย์ ล้อวงศ์งาม

2

Secure Email Validation (OWASP-Aligned & DNS-Strict) (RFC 5322)

Created·2026-01-21 16:32

Updated·2026-01-21 16:36

Flavor·ECMAScript (JavaScript)

This regular expression provides a balance between RFC compliance and security-best-practices. It is designed to prevent injection vectors in legacy systems by using a restricted "safe" character subset recommended by the OWASP Validation Regex Repository. Pattern: ^A-Za-z0-9(?:\.A-Za-z0-9_+&-]+)*@(?:[A-Za-z0-9{0,61}[A-Za-z0-9])?\.)+[A-Za-z]{2,63}$ Key Features: Forced Alphanumeric Start: Prevents leading hyphens to avoid command injection vulnerabilities. Security Subset: Restricts special characters to _+&*- to prevent exotic character injections (e.g., pipes or backticks). No Quoted Strings: Forbids quoted strings to eliminate dangerous payloads containing spaces or backslashes. DNS Compliance: Enforces label lengths (1–63 characters) and prevents labels from starting or ending with hyphens. Whole String Anchoring: Uses ^ and $ to ensure the entire input is validated.

Submitted by Gor Sargsyan

1

Laravel Log (MonoLog) Print

Created·2026-01-21 14:51

Updated·2026-01-21 15:00

Flavor·PCRE2 (PHP)

Extracts the following fields from a Laravel Log print: Time Stamp (Date) Log Level (supports optional prefix (ie. local.DEBUG)) Log Message Exception | Context If an exception is detected, the file reference (file path + line number), and optional stacktrace are captured.

Submitted by Jerren

1

Poland PESEL

Created·2026-01-21 11:23

Flavor·PCRE2 (PHP)

Correct Poland PESEL base regex validator. Covers birth dates up to 2099 year. PESEL numbers are in YYMMDDXXXXX format, however, the month is adjusted based on what year people were born. People born from 1900-1999 has no adjustment, 2000-2099 is the month +20, 2100-2199 is +40, 2200-2299 is +60. For example, if someone was born December 16, 2016, their PESEL would be 163216XXXXX.

Submitted by @Sldmk

1

PLF4 Formular mit Komponente

Created·2026-01-21 07:52

Flavor·PCRE2 (PHP)

Submitted by anonymous

1

PLF3

Created·2026-01-21 07:38

Flavor·PCRE2 (PHP)

Submitted by anonym

1

PLF2

Created·2026-01-21 07:22

Flavor·PCRE2 (PHP)

Submitted by anonym

1

PLF1

Created·2026-01-21 07:20

Flavor·PCRE2 (PHP)

Submitted by anonym

1

Wasser

Created·2026-01-20 20:24

Flavor·PCRE2 (PHP)

hey das ist richtig coool oder?

Submitted by anonymous

1

Python -- Match container image reference parts

Created·2026-01-20 02:14

Updated·2026-01-20 02:28

This is a Python RE for matching different parts and combinations of various docker/container image references, as compatible with docker pull etc. Parts / Capture Groups image: # whole image repo: # everything but the tag/digest registry: # host+port host: port: name: # path within registry reference: # tag or digest (with : or @; I haven't bothered to figure out how to strip that yet) tag: digest: If it matches, it should match image, repo, and name at the very least.

Submitted by neal-ian

1

Check valid URI Scheme according to RFC2396

Created·2026-01-17 07:52

Simple prefix matcher for validating URI Schemes according to [RFC2396, Section 3.1]( http://www.faqs.org/rfcs/rfc2396.html#3.5:~:text=well%20as%20%22http%22%29.-,scheme%20%20%20%20%20%20%20%20%3D%20alpha%20*%28%20alpha%20%7C%20digit%20%7C%20%22%2B%22%20%7C%20%22%2D%22%20%7C%20%22.%22%20%29,-Relative%20URI%20references) Go Playground: https://go.dev/play/p/vtYEugsNAfo

Submitted by Gwyneth Llewelyn

1

URL, URI format validation

Created·2026-01-16 16:16

Updated·2026-01-16 23:25

Flavor·ECMAScript (JavaScript)

URL, URI format validation

Submitted by Atipat Lorwongam

2

Regex Email Format

Created·2026-01-15 17:39

Updated·2026-01-16 23:26

Flavor·ECMAScript (JavaScript)

Used to check Email Format

Submitted by Atipat Lorwongam

1

ตรวจสอบวรรณยุกต์และสระในภาษาไทย (รองรับการลากเสียงอาาาา)

Created·2026-01-15 17:20

Updated·2026-01-23 07:30

Flavor·ECMAScript (JavaScript)

ตรวจสอบการใช้วรรณยุกต์และสระในภาษาไทย รองรับการใช้สระอาาาาาติดกันแบบลากเสียง ไม่ตรวจสอบพยัญชนะต้นและตัวสะกด

Submitted by อธิปัตย์ ล้อวงศ์งาม

1

ตรวจสอบวรรณยุกต์และสระในภาษาไทย

Created·2026-01-15 17:19

Updated·2026-01-23 07:29

Flavor·ECMAScript (JavaScript)

ใช้ตรวจสอบวรรณยุกต์และสระในภาษาไทย ไม่ตรวจสอบพยัญชนะต้นและตัวสะกด

Submitted by อธิปัตย์ ล้อวงศ์งาม

1

Match instagram URLs

Created·2026-01-13 23:29

Flavor·PCRE2 (PHP)

Matches instagram urls for posts, reels, and stories works on all flavors except rust

Submitted by User9684

1

Discord URL matching

Created·2026-01-13 23:19

Updated·2026-01-13 23:24

Flavor·PCRE2 (PHP)

match every type of discord url with each useful part in a group pretty optimized, shouldnt be too harsh on your system should work in every flavor except rust because rust sucks lol

Submitted by User9684

1

Match Bible References

Created·2026-01-12 14:12

Flavor·PCRE2 (PHP)

I've created this for a simple project of mine, it squishes every book of the Bible into a RegEx, with the full name, abbreviation, and abbreviation with a dot. Then, it matches the chapter and verse relatively simply.

Submitted by Twineee

1

cApStAn OmegaT flagged / disallowed text

Created·2026-01-11 22:28

Flagged / disallowed text expression used in cApStAn's build of OmegaT

Submitted by msoutopico

1

cApStAn OmegaT custom tags

Created·2026-01-11 22:26

Custom tags expression used in cApStAn's build of OmegaT

Submitted by msoutopico

1

Caculator seperator with groups

Created·2026-01-08 19:18

Flavor·PCRE2 (PHP)

Caculator seperator with groups

Submitted by CalcMan

1

Simple CSS Selector parser

Created·2025-12-31 14:18

Updated·2025-12-31 14:22

Flavor·ECMAScript (JavaScript)

Basic Regex for CSS Selector. Pseudo-Elements, Combinators and other advanced stuff are not supported.

Submitted by anonymous

1

HP Prime

Created·2025-12-30 04:20

Updated·2025-12-30 15:37

Flavor·PCRE2 (PHP)

Extracts HP Prime PPL numbers.

Submitted by anonymous

1

Strings

Created·2025-12-30 04:09

Updated·2025-12-30 04:11

Flavor·PCRE2 (PHP)

Extracting strings defined in languages like C/C++ etc.

Submitted by Insoft

1

1

Created·2025-12-28 04:09

Submitted by anonymous

1

U.S. Phone Number

Created·2025-12-23 19:40

Flavor·PCRE2 (PHP)

Format validation for U.S. phone numbers with or without a country code and with various formatting and punctuation permissible.

Submitted by Nick

1

AoC 2025 Day 5

Created·2025-12-19 23:04

AoC 2025 Day 5 part 1 but also works for part 2. You just don't need the IDs at the bottom for part 2

Submitted by anonymous

1

Telephone validation regex - handles international codes, extensions, and formatting gracefully

Created·2025-12-19 21:17

Flavor·PCRE2 (PHP)

Search string for use in contact cleaning project $1 = intenational code, omitting preceding "+" $2 = area code $3 = first three digits of phone number $4 = last four digits of phone $5 = extension, inclusive of any commas or hashes to automate phone tree navigation TO DO handle recursive menus (e.g., "321-321-1234,,,1234#,,123344#....)

Submitted by Jason

1

Changes Log Tag verify for Languages Code sub-versioning

Created·2025-12-18 10:41

Flavor·PCRE2 (PHP)

Search for the occurence of the 3 following words: CHA, LOG and TAG. Should be in the above order sequence (but it also if works swapped).

Submitted by XrosaXasorX

1

Asw

Created·2025-12-17 05:38

Flavor·PCRE (Legacy)

``/^(?P0|1-9]\d)\.(?P0|[1-9]\d)\.(?P0|[1-9]\d)(?:-(?P(?:0|[1-9]\d|\d[a-zA-Z-)(?:\.(?:0|1-9]\d|\d[a-zA-Z-))))?(?:\+(?P[0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$/gmsAD

Submitted by anonymous

1

DoubleQuote Enclosed CSV Field with Escaped DoubleQuote

Created·2025-12-11 12:04

Flavor·PCRE2 (PHP)

Extract field value of DoubleQuote Enclosed CSV Field with Escaped DoubleQuote The matching field value still contains escaped double quotes to be later processed :-)

Submitted by Alper YAZGAN

Community Library Entry

1

Regular Expression
Created·2024-08-25 15:52
Updated·2024-08-26 08:27
Flavor·ECMAScript (JavaScript)

/

^[a-z0-9]+(?:[.\-_'+][a-z0-9]+)*@([a-z0-9]+(?:[-][a-z0-9]+)*\.)+[a-z]{2,}$

/

igm

Open regex in editor

Description

"/" - start of regular expression "^" - anchor to beginning of string

Group: [a-z0-9]+ "[a-z0-9]" - Latin character or digit "+" - occurring ONE or more times

Group: (?:[.-][a-z0-9]+)* "(" - start of group "?:[.-_'+][a-z0-9]" - first character of group is allowed to be single character "." OR "-", followed by Latin character or digit "+" - occurring ONE or more times ")" - end of group "*" - group occurs ZERO or more times

"@" - mandatory single at sign

Second-level domain group and below: ([a-z0-9]+(?:[-][a-z0-9]+).)+ "(" - start groups "[a-z0-9]" - Latin character or digit "+" - occurring one or more times "(" - beginning of subgroup "?:[-][a-z0-9]" - single hyphen mandatory for subgroup, followed by Latin character or digit "+" - one or more times ")" - end of subgroup "" - subgroup occurs ZERO or more times "." - mandatory single dot ")" - end of group "+" - occurring ONE or more times

Top-level domain group: [a-z]{2,}$ "[a-z]" - Latin character "{2,}" - occurring TWO or more times

"$" - anchor to end of line "/" - end of regular expression "i" - expression case-insensitive flag (makes ranges [a-z] and [a-zA-Z] equivalent)

"gm" - only for success validation multiline in Test string section, these flags not needed in checking once string value

Submitted by Diableros [https://github.com/Diableros]