Hi,
To summarize your requirements,
Json submission to server needs to be done using API. And json will be dynamic each time.
Wen development language is your choice, you tell you want in php or asp.net? I m expert in both.
I am a json expert and a web API expert. You may check my related work in my projects.
Web Development Career:
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Experience:
Have developed many web applications (based on Wordpress, .NET, MVC, SQL Server), Web GIS Applications (Open Source Geoserver, Postgresql plus .NET and PHP based), Desktop Software Apps (.Net + SQL Server)
Fields:
ASP.net, VB.net,
Classic ASP
PHP,
Wordpress,
React Native etc.
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Regards,
Eagle Eyes