Backend for checking payments and giving users access to data if payment was done... - repost

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Project Budget (USD)
$250 - $750

Project Description:
It concerns a mobile app that I am building at the moment with App Inventor that needs a backend (i.e. web application) with Google App Engine as the backend for datastore and scaling of the requests. The backend would consist of a system where users can login and have
access to certain info when they have paid for the access to the info. The info is generated in the mobile app and saved to a datastorage (tag/value) with App Inventor and Google Ap Engine. The backend would be accessible either via the mobile app or via the web application via the browser.

There would need to be programmed the logic that checks if users have paid with either Paypal ( and/or neteller (
and/or Google Checkout ( So those API's are involved as well. If they have paid, they can get the access to the info (that was send via the mobile app that I am making at the moment...) If they haven't paid, they should get a popup that they will need to pay for access to the data and be able to chose the payment system (Paypal, Neteller, Google Checkout and maybe Ideal payments in the near future if possible..)
Then after the user pays for access to the data they should be able to access the data (automatically after paying or manually after logging in at the backend with their email-adress as username and a password...)

So the question is if a freelancer would be able to program such a system with the needed programming languages (Paypal API uses either Java, PHP, C# or Perl) and Google App Engine (for the datastore) uses Python (or Java or Go..) Neteller uses forms with HTTP requests (Post and Get) with HTTP Value/Pairs and/or XML parsing...(see the attached Neteller API-doc for details about the neteller API for example...) Google Checkout makes use of a Google Checkout JAVA SDK...See the following URL for more details:

Sandbox accounts can be created with the payment providers to test the whole payment process and the process after the payment to let the user access the data that was stored via the mobile app. Test payments can be done with the sandbox accounts and test credit card numbers from the payment providers (i.e. Google, Paypal, Neteller) After the testing with the sandbox accounts Real info will be provided that has to be programmed in order to let the programmed logic work with real life payments. After this has been tested and succeeded the project will be completed and be considered successfull.

Details of the mobile app and how the data has to be handled will be given upon acceptance of the project and agreement about the price of the whole project. A Non-Disclosure Agreement will have to be signed, scanned and emailed before starting the project.

Skills required:
Graphic Design, HTML, PHP, Website Design, XML
Additional Files: NETELLER_Direct_v4.1.3_API_Documentation.pdf
Hire korthoutapps
Project posted by:
korthoutapps Netherlands
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