I invite you to have a look at my application SilentNotes;
It is a FOSS application which I have developed with a strong focus on privacy.
The notes can be synchronized end-to-end encrypted between multiple Android and Windows devices and can be self-hosted. Currently supported are the FTP protocol, the WebDav protocol, Dropbox, Google-Drive and One-Drive.
Threema would fit your requirements almost completely:
Isn't owned by Facebook, inc.: Nope. It's owned by Swiss-based Threema and has a strong focus on privacy. So it's just the opposite to those "kraken"
Is gratis to use: Using it is gratis, yes. There's just a very reasonable one-time fee for the license (less than 3 bucks). Per device that is (you can ...
Not an app, but a website. Pixabay claims to have more than 1 million free images, illustrations, vector images and videos. All searchable and filterable by image type, size, orientation, color and category. From the website:
Pixabay is a vibrant community of creatives, sharing copyright free
images and videos. All contents are released under the ...
It doesn’t matter which RDMS you use (personally, I like MySql, or its fork MariaDB).
Your mobile app should send the data to a server app via AJAX, by HTTPS (use POST, rather than GET, for security).
Only the server app should able to write to the database; the mobile clients should not be able to write to it directly.
Personally , I would code the ...