How to Use the Regex Tester
Regular expressions are powerful but notoriously tricky to write correctly. The ToolPrime Regex Tester lets you write patterns and instantly see matches highlighted in your test string. Toggle flags (global, case-insensitive, multiline, dotall), inspect capture groups, and track match indices — all in real time.
1 Open the Regex Tester
Navigate to the Regex Tester tool page.
2 Enter your pattern
Type your regex pattern in the pattern input field.
3 Add test text
Paste or type the text you want to test against in the text area below.
4 Review matches
Matches are highlighted in real time. Capture groups and match details are displayed below.
Common Use Cases
- Validating email addresses, phone numbers, and URLs
- Extracting data from log files or structured text
- Building search-and-replace patterns for text editors
- Learning regex by experimenting with patterns and flags
Pro Tips
Use the global (g) flag to find all matches, not just the first one.
The case-insensitive (i) flag makes your pattern match regardless of letter case.
Named capture groups (?<name>...) make complex patterns more readable.
Try it yourself
Open Regex Tester