All tools
Password Breach Checker
Check whether a password appears in a known data breach, without ever sending it anywhere. Your browser hashes it and sends only the first five characters of that hash.
How this stays private: your browser computes the SHA-1 hash and sends only the first five characters. The service returns every breached hash sharing that prefix - hundreds of them - and the match happens back in your browser. This is called k-anonymity, and it means nobody on the wire or at either end learns your password.
More tools
All 16JWT Decoder & Verifier
Decode a JSON Web Token to inspect header and payload, check expiry, and verify the signature (HS* with a secret, RS*/ES* with a public key). Decoding stays in your browser.
One-Time Secret
Share a password or note via a link that self-destructs after one view. Encrypted in your browser - the key never reaches the server.
Email Validator
Check an email address: valid syntax, a live MX-record lookup to see if the domain accepts mail, and disposable or role-based flags.