Online Regex Tester
Test, debug, match and replace text using regular expressions.
Regular Expression
Ready-to-Use Regex Examples
Test Text
Match Summary
0
Total Matches
0
Unique Matches
0
Capture Groups
Your highlighted matching text will appear here.
Match Details
No match results yet. Enter a pattern and test text.
Find and Replace
Replacement output will appear here.
Note: This tool uses the native JavaScript Regular Expression engine. Regex syntax and behavior may differ from Java, Python, PHP and other programming languages.
Free Online Regex Tester – Test, Debug & Validate Regular Expressions
Regular expressions (Regex) are powerful patterns used to search, match, validate, and extract specific text from strings. Whether you are a developer, tester, student, or data analyst, regular expressions can help you perform complex text-processing tasks quickly and efficiently. Our **Free Online Regex Tester** allows you to write regular expression patterns, test them against sample text, highlight matches, view detailed match information, and find and replace text directly in your browser. No registration, installation, or external API is required. Use this online Regex Tester to practice regular expressions, debug patterns, validate text formats, and extract useful information from your test data.What Is an Online Regex Tester?
An Online Regex Tester is a browser-based tool that helps users create, test, and debug regular expressions. It checks whether a particular pattern matches the text you provide and displays matching results instantly. Instead of manually searching through large text files, you can use Regex patterns to find email addresses, numbers, dates, URLs, names, and other specific text formats. This tool uses JavaScript regular expressions and provides live matching results, highlighted text, match details, and a convenient Find and Replace feature.Key Features of Our Free Regex Tester
- Live Regex Testing: Automatically displays matching results when you change the regex pattern or test text.
- Multiple Regex Flags: Supports Global, Ignore Case, Multiline, Dot All, and Unicode flags.
- Ready-Made Regex Examples: Try commonly used patterns for emails, URLs, numbers, dates, and more.
- Match Highlighting: Easily identify matching text within your original content.
- Detailed Match Information: View match numbers, matched text, start positions, end positions, and capture groups.
- Find and Replace: Search for matching text and replace it with new content using regular expressions.
- Replacement Preview: Preview the modified text before copying the result.
- Copy Results: Conveniently copy highlighted or replacement results.
- No Installation Required: Use the tool directly in your web browser.
- Browser-Based Processing: Your text is processed locally in your browser without sending it to an external extraction API.
How to Use the Online Regex Tester
Follow these simple steps to test and validate your regular expressions:Step 1: Enter a Regex Pattern
Enter your regular expression in the Regex Pattern field. You can write your own pattern or select one of the ready-made examples available in the tool.Step 2: Select Regex Flags
Choose the required flags according to your testing needs. You can enable Global, Ignore Case, Multiline, Dot All, and Unicode options.Step 3: Enter Your Test Text
Paste or type the text you want to test in the Test Text field. The tool automatically checks the text against your regular expression and displays the results.Step 4: Review Matching Results
Check the highlighted matches and Match Details section to understand which parts of your text match the pattern.Step 5: Use Find and Replace
Enter the replacement text to replace matching content. You can preview the updated text and copy the result when needed.Understanding Regex Flags
Regex flags change how a regular expression searches and matches text. Our Online Regex Tester supports five commonly used JavaScript regex flags. Below are practical examples to understand how each flag works.1. Global Flag (g)
The Global (g) flag finds all matching occurrences in the text instead of stopping after the first match.Regex Pattern:
sleepTest Text:
9 hours of sleep 7.5 hours of sleep 6 hours of sleepWithout Global (g):
Match 1: sleepWith Global (g):
Match 1: sleep Match 2: sleep Match 3: sleepExplanation: Without the Global flag, the regex returns only the first match. When you enable the Global flag, it finds all three occurrences of the word "sleep".
2. Ignore Case Flag (i)
The Ignore Case (i) flag matches uppercase and lowercase letters without considering case differences.Regex Pattern:
helloTest Text:
Hello World HELLO FRIEND hello everyoneWithout Ignore Case (i):
Match 1: helloWith Ignore Case (i) and Global (g):
Match 1: Hello Match 2: HELLO Match 3: helloExplanation: Without the Ignore Case flag, the pattern "hello" matches only lowercase text. When you enable the Ignore Case flag, it also matches uppercase and mixed-case variations.
3. Multiline Flag (m)
The Multiline (m) flag changes the behaviour of the start (^) and end ($) anchors so they can match the beginning and end of individual lines.Regex Pattern:
^sanviTest Text:
sanvi is good girl lakshya is good boy sanvi is best and kevalWithout Multiline (m) and with Global (g):
Match 1: sanviWith Multiline (m) and Global (g):
Match 1: sanvi Match 2: sanviExplanation: Without the Multiline flag, the ^ anchor matches only the beginning of the complete text. When you enable the Multiline flag, it can also match the beginning of each new line.
4. Dot All Flag (s)
The Dot All (s) flag allows the dot (.) character to match newline characters as well. Normally, a dot matches most characters except line terminators.Regex Pattern:
hello.worldTest Text:
hello worldWithout Dot All (s):
No match foundWith Dot All (s):
Match 1: hello worldExplanation: Without the Dot All flag, the dot (.) cannot match the newline between "hello" and "world". When you enable the Dot All flag, the dot can match that newline character, allowing the complete pattern to match.
5. Unicode Flag (u)
The Unicode (u) flag enables Unicode-aware regular expression matching and supports Unicode property escapes, which help identify letters and other character categories from different languages.Regex Pattern:
\p{L}+
Test Text:
Hello नमस्ते BonjourWith Unicode (u) and Global (g):
Match 1: Hello Match 2: नमस Match 3: BonjourExplanation: The Unicode flag allows the pattern to use Unicode property escapes such as \p{L}, which matches Unicode letters. In this example, the Latin and Devanagari letters are matched. The Devanagari vowel sign in "नमस्ते" is a combining mark, not a letter, so it is not included in the matched text. Note: The Unicode flag is useful when working with text containing characters from different languages and Unicode character sets.
Common Regex Patterns and Their Uses
Regular expressions use special characters and symbols to define search patterns. These symbols help you find numbers, letters, words, spaces, dates, and other specific text formats quickly. Below are some commonly used regex symbols and ready-to-use pattern examples that you can try in our Online Regex Tester.1. Common Regex Symbols
- \d – Matches any digit from 0 to 9.
- \D – Matches any character that is not a digit.
- \w – Matches letters, digits, and underscores (A-Z, a-z, 0-9, and _).
- \W – Matches any character that is not a word character.
- \s – Matches whitespace characters such as spaces, tabs, and newlines.
- \S – Matches any character that is not whitespace.
- . – Matches any character except line terminators, unless the Dot All (s) flag is enabled.
- + – Matches one or more occurrences of the preceding character or pattern.
- * – Matches zero or more occurrences of the preceding character or pattern.
- ? – Matches zero or one occurrence of the preceding character or pattern.
- ^ – Matches the beginning of the text or, with the Multiline flag, the beginning of a line.
- $ – Matches the end of the text or, with the Multiline flag, the end of a line.
- [abc] – Matches any one character from the specified character set.
- [^abc] – Matches any character except the specified characters.
- {n} – Matches exactly n occurrences of the preceding character or pattern.
- () – Creates a capturing group to extract a specific part of a match.
2. Ready-to-Use Regex Pattern Examples
You can copy these patterns and paste them into the Regex Pattern field of our Online Regex Tester to find matching text.Example 1: Find Numbers Regex Pattern:
\d+Test Text:
My age is 35 and my phone number is 9876543210.Expected Matches:
35 9876543210Example 2: Find Words and Letters Regex Pattern:
\w+Test Text:
Hello Java_95! Welcome to Regex Testing.Expected Matches:
Hello Java_95 Welcome to Regex TestingExample 3: Find Whitespace Regex Pattern:
\s+Test Text:
Hello Java Tutorial 95Expected Matches:
Example 4: Find Email-Like Text Regex Pattern:
[\w.+-]+@[\w.-]+\.[A-Za-z]{2,}
Test Text:
Contact us at support@example.com or admin@gmail.com.Expected Matches:
support@example.com admin@gmail.comExample 5: Find URLs Regex Pattern:
https?://[^\s]+Test Text:
Visit https://example.com and http://google.com for more information.Expected Matches:
https://example.com http://google.comExample 6: Find 10-Digit Numbers Regex Pattern:
\b\d{10}\b
Test Text:
Call 9876543210 or 1234567890 for assistance.Expected Matches:
9876543210 1234567890Example 7: Find Dates in YYYY-MM-DD Format Regex Pattern:
\b\d{4}-\d{2}-\d{2}\b
Test Text:
Start date: 2026-11-04 and end date: 2026-12-31.Expected Matches:
2026-11-04 2026-12-31Example 8: Find Words Starting with a Specific Letter Regex Pattern:
\bS\w*Test Text:
Sanvi is studying Software and Science.Expected Matches:
Sanvi Software ScienceExample 9: Find Decimal Numbers Regex Pattern:
\d+(?:\.\d+)?Test Text:
Prices are 99, 149.50, and 250.75.Expected Matches:
99 149.50 250.75Example 10: Find Text Inside Parentheses Regex Pattern:
\(([^)]+)\)Test Text:
Java (Programming) and Python (Scripting) are popular languages.Expected Matches:
(Programming) (Scripting)Capture Group 1:
Programming ScriptingNote: These regex patterns are useful for common text-matching tasks, but they do not guarantee complete validation of complex formats such as email addresses, URLs, phone numbers, or calendar dates. Always test patterns against your actual data and requirements.
Common Uses of Regular Expressions
Regular expressions are useful in many programming, testing, and data-processing tasks.- Email Extraction: Find email addresses in large text documents.
- Number Validation: Match phone numbers, numeric values, and other number formats.
- Date Validation: Identify dates in formats such as YYYY-MM-DD.
- URL Matching: Search for website URLs within text.
- Text Replacement: Replace specific words, numbers, or matching patterns.
- Data Cleaning: Find unwanted characters, extra spaces, and inconsistent text formats.
- Software Testing: Validate input formats and test regular expression patterns during development.
Frequently Asked Questions (FAQs)
1. What is a regular expression (Regex)?
A regular expression is a sequence of characters that defines a search pattern. It is commonly used to find, match, validate, and replace specific text in programming and data-processing applications.2. Is this Online Regex Tester free to use?
Yes. Our Online Regex Tester is completely free to use. You can test regular expressions, view matching results, and use Find and Replace without registration or installation.3. Can I test email addresses using this Regex Tester?
Yes. You can use a regular expression pattern to identify and match email-like text formats. However, matching an email pattern does not guarantee that an email address exists or is valid for delivery.4. What is the difference between Global (g) and Multiline (m) flags?
The Global (g) flag finds all matching occurrences in the text, while the Multiline (m) flag changes how the start (^) and end ($) anchors work across multiple lines. Both flags can be used together.5. What are Capture Groups in Regex?
Capture Groups are parts of a regular expression enclosed in parentheses. They allow you to extract specific portions of a matched string. For example, the pattern (\d{4})-(\d{2})-(\d{2}) captures the year, month, and day separately.6. Can I find and replace multiple matches at once?
Yes. Enable the Global (g) flag to replace all matching occurrences in the text. You can also use capture group references such as $1 and $2 in the replacement field.7. Does this Regex Tester support Java, Python, and PHP regular expressions?
This tool uses the built-in JavaScript regular expression engine. Although many basic regex patterns work across different programming languages, some advanced syntax and features may vary between JavaScript, Java, Python, and PHP.8. Is my text uploaded to a server when I use this tool?
No. The tool processes your patterns and test text locally in your browser. Your entered content is not sent to an external extraction API.Explore More Free Online Tools
You may also find these useful tools helpful for programming, testing, and data processing:- Email Extractor Online
- SQL Mock Data Generator
- Random Test Data Generator
- Text Sorter
- JSON Formatter and Validator
