Regex Tester & Validator

This regular expression matches and captures any sequence of characters that is directly wrapped between two literal periods (dots). Using positive lookbehind and lookahead assertions, it extracts the inner text without including the delimiters themselves. With the global and multiline flags, it is highly effective for extracting individual segments or nested keys from dotted configuration strings, such as extracting 'config' from 'system.config.setting'.