Zwisper

Say it without saying it. Private notes hidden in messages within your apps. End-to-end encrypted.

Hide private notes inside ordinary messages. Zwisper works inside websites you already use, such as Gmail, Slack and WhatsApp Web. Write a normal message, add an encrypted note, and send it as usual. The message everyone sees stays readable and looks unchanged. A recipient with Zwisper can open the private note using a saved contact or a one-time password. HOW IT WORKS 1. Turn Zwisper on for a website. 2. Write your normal message. 3. Click Hidden note and type the private part. 4. Choose a contact or set a one-time password. 5. Hide the note, then send the message normally. Zwisper checks that the website kept the note and warns you if it did not. READING NOTES Messages containing a Zwisper note are underlined in purple. Notes from saved contacts can open automatically and are marked verified. Other notes ask for the one-time password. MAIN FEATURES • Works in ordinary website text fields. • One-time passwords for quick private notes. • Encrypted contacts for trusted conversations. • An optional local inbox for notes you have opened. • Reveal links for people who do not have Zwisper. • Available in 20 languages. • A one-minute practice tour for new users. YOUR PRIVACY Zwisper has no account and no message server. Notes, contacts, passwords and settings stay inside your browser. Encryption happens on your device. During setup, you can accept anonymous diagnostics or continue without them. SITE ACCESS Zwisper starts with access to no websites. You choose where it runs, and your browser asks before granting access. You can remove a website at any time in Zwisper Settings or your browser's extension controls. GOOD TO KNOW Some websites remove the invisible characters that carry a note. Zwisper checks the editor and warns you when this happens. A screenshot will not include the hidden note. A website may be able to detect that invisible characters are present, even though it cannot read the encrypted note. Zwisper is designed for private notes between people you trust. It does not make messages invisible to the website or to someone actively looking for hidden data.