How Locked Chats Protect Private Conversations

The problem Chat Lock solves

Most privacy leaks on a phone are not sophisticated attacks — they are someone glancing at your screen while you have a conversation open, or picking up your unlocked phone to check the time and seeing a message preview they were not meant to see. Chat Lock exists for exactly that everyday scenario: it moves a specific conversation out of your main chat list into a separate Locked Chats folder that will not open without proving it is really you.

Chat Lock is included with Stitch Plus, and you can lock as many one-to-one or group chats as you like.

How authentication works — no Stitch code to remember

Older versions of many apps used a separate PIN you set up specifically for the app. Stitch does not do this. Instead, Chat Lock authenticates entirely through your device's own security: Face ID, Touch ID, or fingerprint on a phone, falling back to your device passcode, PIN, or pattern if biometrics are unavailable or cancelled. On the web, Chat Lock uses a passkey or platform authenticator — Windows Hello, Touch ID in Safari, or your device's screen lock — with the same no-code approach.

This matters because it means Stitch never stores a passcode, a biometric template, or any secret of its own for Chat Lock. Your device or browser performs the check and simply reports back whether it succeeded.

Locking and unlocking a chat

1. To lock a chat: open it, tap the name or group info at the top, and turn on Chat Lock — or press and hold the chat in your list (right-click on the web) and choose Lock Chat.
2. The chat immediately leaves your main inbox and moves into the Locked Chats folder, and its notifications become generic (no sender name or message text).
3. To open Locked Chats, tap the folder and authenticate with your device. This is required every time — there is no way to open a locked chat without it.
4. To move a chat back to your normal inbox, open Locked Chats, press and hold the chat (right-click on web), and choose Unlock Chat. Your full message history stays intact.

Which chats stay locked, and on which devices

Which chats you have locked is stored on your account, so it follows you: if you sign in on another phone, tablet, or the web, the same conversations show up in Locked Chats there too. What does not follow you is the unlock itself — authenticating on your phone does not unlock the folder on your laptop, and vice versa. Each device requires its own authentication, which is the correct behavior for a privacy feature: unlocking on one device should never silently expose the same content on another.

Unlocking versus resetting — a critical difference

This is the single most important thing to understand about Chat Lock. Unlocking a chat (from inside the Locked Chats folder) is non-destructive: it moves the conversation back to your inbox and keeps every message. Resetting Chat Lock is the opposite — it is a deliberately destructive safety valve for someone who can no longer authenticate at all (for example, after removing their device's screen lock), and it works by permanently clearing the message history of every currently locked chat before returning them, blank, to the inbox.

Reset only affects your own copy of the conversation. It does not delete the other participant's messages or media from their account. Because reset cannot be undone, Stitch shows a clear warning before you confirm it — use Unlock Chat for everyday changes, and only use Reset Chat Lock when you genuinely cannot get in any other way.

What Chat Lock is not

Chat Lock is a privacy and convenience feature, not message encryption, and it is not a guarantee against every form of access — someone who can unlock your device itself, or who already has access to your signed-in account, may still be able to reach your chats. Separately from Chat Lock, Stitch protects your data with standard encryption in transit and at rest; Stitch is not end-to-end encrypted. For the complete picture, read the Privacy & Safety guide.

Deciding which chats are worth locking

Chat Lock is most useful for conversations where the content itself is what you want protected from a casual glance — not necessarily your "most secret" chats in some abstract sense, but the ones where a preview showing up on your lock screen or a message left open on your desk would actually bother you. This is highly personal: some people lock a single conversation, others lock several. There is no limit that pushes you toward locking more or fewer chats than genuinely makes sense for how you use your phone.

What happens to notifications from a locked chat

Once a chat is locked, its notifications stop showing the sender's name or the message content — you still get alerted that something arrived, but the notification itself reads generically rather than previewing what was said or who said it. This matters in the exact scenario Chat Lock is designed for: someone glancing at your lock screen sees that you got a notification, not what it says or who it is from, closing the gap that a normal message preview would otherwise leave open even with the chat itself hidden.

A realistic mental model

The clearest way to think about Chat Lock is as a door with a lock on it, not a vault. It stops someone from casually wandering into a conversation they were not invited to see, using the same authentication you already trust to protect the rest of your phone. It does not create a separate, stronger security boundary than your device already has — if your device itself is compromised or unlocked by someone else, Chat Lock is not designed to survive that. For that reason, Chat Lock and general account security (a strong password, careful phishing awareness) work best together rather than as substitutes for each other.