Regex Tester

Writing a validation pattern for a phone number, email, or product code is where regex confidence dies. A pattern that matches the happy path also accepts garbage, and one that is too strict rejects real users. The tester lets you paste realistic samples, including the empty string and the trickiest production inputs, then watch each match highlight live. Verify capture groups and the flags you will ship with before the pattern reaches your validation code. Everything runs in the browser, so test data never leaves your device.

Log lines are where regex earns its keep. A request-log entry holds a timestamp, IP address, method, path, status code, and latency, and one pattern can pull any subset into capture groups. Build the pattern in the tester against real log lines, not idealized ones: actual logs contain variable spacing, missing fields, and unusual characters that break hand-written patterns. Verify each capture group, check that lazy and greedy quantifiers behave as intended, and confirm the pattern stays fast on long lines before running it over thousands of entries.