RegexOne
Learn regex through short lessons with live, typed exercises
RegexOne teaches regular expressions through short lessons. Each lesson explains one idea, then gives you an exercise. You type a pattern, and the text it matches is highlighted as you type. You finish the task to move on to the next lesson.
Free · No login · Browser · Beginner
About RegexOne
The lessons start with letters and digits and move on to character classes, repetition, anchors and capture groups. After the lessons, practice problems ask you to match real things such as phone numbers, emails, file names, log lines and URLs. It suits complete beginners.
The site runs in the browser, is free and needs no account. You can donate to support it if you like. It also has reference pages on using regex in Python, JavaScript, Java, C# and PHP.
On Breakpoint since 23 Oct 2026.