[@TK] Using LeakCheck locally is significantly safer than a browser because your plaintext password never leaves your machine, protecting it from malicious browser extensions or compromised scripts. The rainbow table concern is mathematically invalid due to K-Anonymity: LeakCheck hashes your password locally and sends only the first 5 characters of that hash to the API. The API returns a list of matching partial hashes, and the actual comparison is completed locally on your device. Since the external service never receives your full hash or plaintext password, it is impossible for anyone to reverse-engineer your data using rainbow tables.