Regex Tester
NewTest regular expressions interactively with real-time match highlighting, flags toggle, and a match list. Supports all JavaScript regex flags (g, i, m, s, u) and shows each match with its index position. Perfect for debugging patterns, learning regex, and validating input patterns.
How to Use Regex Tester
- 1Enter your regex pattern
- 2Toggle flags as needed (g, i, m, s, u)
- 3Type or paste the test string
- 4See matches highlighted in real time
About Regex Tester
Test regular expressions interactively with real-time match highlighting, flags toggle, and a match list. Supports all JavaScript regex flags (g, i, m, s, u) and shows each match with its index position. Perfect for debugging patterns, learning regex, and validating input patterns.
Your Privacy is Protected
Regex Tester runs entirely in your browser. Your files and data are never uploaded to any server, never stored, and never shared. Everything happens locally on your device using secure browser APIs.
Frequently Asked Questions
What flags are supported?
g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode).
Why isn't my regex matching?
Check for missing flags. Without the g flag only the first match is found. Without i flag matching is case-sensitive.
Why Use This Tool?
Tags
Related Tools
More Developer Tools
View all Developer ToolsRelated Articles
JSON Formatter and Validator — How to Use It Like a Pro
8 min readBest Free Developer Tools Online in 2026 — No Install, Instant Results
9 min readHow to Format JSON Online — Free JSON Formatter & Validator (2026)
6 min readTry Regex Tester Now
Free, instant, no login. Use it right now — directly in your browser.
Use Regex Tester Instantly