こそっとみる LINE 既読防止 is a simple Android app developed by yukkieeeeee that allows you to read LINE messages without marking them as read. With this app, you can easily check your messages without having to turn on the airplane mode or worrying about marking them as read.

To use the app, simply launch it and turn on the "こそっとみる" switch in the settings. Then, wait for LINE messages to arrive. The app is very easy to use, and it is the simplest app among all the other read receipt blocking apps.

However, it is important to note that the app only works with individual chats and does not support group chats. Additionally, you cannot view contents such as text, stamps, and photos, and you cannot send messages or delete messages from LINE.

Overall, こそっとみる LINE 既読防止 is a useful app for those who want to read LINE messages without marking them as read. It is simple to use and works well, as long as you have the necessary LINE notification settings enabled.