Your goal is to guess the secret regular expression!

  1. Test character sequences, to learn whether they match the regex.
  2. When you think you know the regex, click the blue button below.
  3. If your guess is wrong, you will get a counterexample.

Example: You learn that the words banana, guacamole and macadamia match the regex, but cucumber, raspberry and peas do not. You see that all matching words contain two "a", separated by another character, and guess the equivalent regex: a.a

Matching strings:

Non-matching strings:

Regex guesses: