To half swipe on Snapchat and preview a message without triggering the "opened" notification, follow these steps carefully:

1. Open Snapchat and go to the Chat tab by swiping left or tapping the chat icon at the bottom.
2. Find the conversation you want to preview.
3. Tap and hold on the sender’s Bitmoji or profile icon on the left side of the chat. Do not tap the chat itself.
4. While holding your finger down, gently swipe to the right just enough to reveal a sliver of the message preview. Do not swipe too far.
5. Read the message while keeping your finger on the screen.
6. When done, carefully swipe back to the left to close the preview, still without lifting your finger.
7. Only release your finger after the chat returns to its original position.

If done correctly, the message will remain marked as unread, and the sender will not get a read receipt

Important Tips:

• Only works for text messages, not Snaps (photos/videos).
• Swiping too far or lifting your finger too early will open the message fully and notify the sender.
• Snapchat Plus users with the "Peek a Peek" feature enabled can detect half swipes.
• Practice the motion to avoid accidental full opens

This trick works on both iPhone and Android devices as of 2025 but may break with future Snapchat updates since it is not an official feature