Extract Data from Text with Regex Patterns
Test and debug regular expressions with real-time matching. Extract emails, URLs, phone numbers, and structured data from text.
The Problem
You need to extract all email addresses from a log file, validate phone number formats, or parse structured data from text. You write a regex, but you're not sure it handles edge cases. Testing in code requires a full edit-run cycle.
Why This Matters
Regular expressions are one of the most powerful text processing tools available in every programming language. A well-written regex can replace dozens of lines of string manipulation code. Testing your pattern against real data before integrating it into production code catches edge cases early and saves debugging time.
Step-by-Step Instructions
Enter your regex pattern
Type your regular expression in the pattern field without the surrounding slashes. Example: [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,} for email matching.
Set flags if needed
Common flags: g (global — find all matches, not just first), i (case-insensitive), m (multiline — ^/$ match line starts/ends).
Paste your test text
Enter the text you want to search. Use real sample data — log lines, email dumps, API responses, or whatever your production input looks like.
See highlighted matches
Matches are highlighted in real time. Check that you're matching exactly what you intend — and not matching things you shouldn't.
Try It Now — Regex Tester
Open full page →All processing happens in your browser — no data is sent to any server.
Before & After Example
2026-03-07 10:23:41 INFO User [email protected] logged in from 192.168.1.100 2026-03-07 10:24:15 ERROR Failed login for [email protected] from 10.0.0.55 2026-03-07 10:25:02 ERROR Failed login for [email protected] from 203.0.113.42 2026-03-07 10:25:44 INFO User [email protected] logged in from 192.168.1.101 2026-03-07 10:26:11 ERROR Failed login for admin from 198.51.100.7
Pattern: (?<=ERROR.*from )\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}
Flags: gm
Matches found:
10.0.0.55
203.0.113.42
198.51.100.7
→ 3 suspicious IPs to block in your firewall
Frequently Asked Questions
What regex flavor does this use?
JavaScript regex (ECMAScript). The syntax is compatible with Python (with minor differences), Perl, and most modern languages. Java and .NET have some syntax differences for advanced features.
How do I match a literal dot, plus, or asterisk?
Escape them with a backslash: \. matches a literal dot. \+ matches a plus. Without the backslash, . matches any character.
What's the difference between greedy and lazy matching?
.* is greedy — matches as much as possible. .*? is lazy — matches as little as possible. Lazy matching is better for patterns like extracting content between tags.
Related Workflows
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