I Am Searching From Long Time In Different Community Of App Inventor But I Do Not Found Any Solution ,
I Am Searching How Whatsapp Store There Message In Our Device ? Can We Make The Apps Like This In Kodular ?
When User Open The My Apps It’s Recognize If Any Message Received So It’s Store In Device And Show It In Order And User Can Not Delete It Easily If Anyone Have Any Solution So Share It
When you got messages from database store them in tinydb, so it can be saved locally too.
But User Can Change It In Realtime
Use Cryptography Component to Encrypt-Decrypt them or any other method 
So We Need To Store Each Persons Id As A Tag And Messages In The List As A Value With Encrypted Functions ?
What Is Capacity Of TinyDB
Can’t say exactly what to do, because I have never tried, you can spend some time and make your own method to store and secure messages.
Huh…Nice Question, but IDK 
It depends on user device free storage.
If free storage is 64gb then tiny db capacity will be 64gb.
Tiny db data is stored in internal storage of the device in xml format.
Are You Sure ? Kiran !
Yes. I read it somewhere in the community.
But As Taifun Said There Is Some Limitation !
And I Am Sure When We Store Around 5k Message Of Different User’s So It’s May Crash Application
Same …
You can store message as a json and use them to show in chatview 
As there is no limit for number of charectors in tiny db, If you store it in proper way then there will be no issues.
Dictionaries may be useful along with tiny db.
Also you can use multiple tiny db components to reduce load on single tiny db.
Is TinyDB Is Good Idea For It , It Difficult To Decide !
But If There Any Way To Read And Edit Any Files And Change The Extension
For Example If I Create The .txt File And Store Message In There And Read It And Change The Extension That User Can Not Access
What You Both( @themaayur , @The_K_Studio ) Think About It
Txt file is better idea…
Change the text file name extention when file created…
Like
Myfile.txt and after created change to Myfile.db…
When read then again change to Myfile.txt…
You can go with .txt file also but not necessary to change its extension to hide it from user.
You can store that file in a hidden folder by setting … Before file path.
I don’t remember it 
search in community
