A regex tester is an online tool that helps developers test and debug regular expressions in real-time. It allows you to input a pattern, apply flags, and instantly see matches, groups, and any errors.

Regular expressions (regex) are sequences of characters that define search patterns, primarily used for string matching and validation. This tester supports JavaScript-style regex with common flags like g (global), i (case-insensitive), m (multiline), and more.

Use this tool to validate emails, URLs, phone numbers, or any custom pattern. Save your patterns for later, explore built-in examples, and get instant feedback on match counts, positions, and captured groups.