Development and customization is nearly same as in SharePoint
On-premises with some exceptions as the below:
- You can only use Sandbox solutions with SharePoint Online Standard model
- You can use Farm solutions (Full trusted code) with SharePoint online Dedicated model with some guidelines form Microsoft (Microsoft SharePoint Online Code Analysis Framework (MSOCAF))
- Any Customization with SharePoint Designer , InfoPath or browser same as SharePoint On-premises
- Trick ( to deploy Visual Web Part as Sandbox solution) use SharePoint Power Tools template which also sandbox –aware tools which check if your code can run in sandbox solution
- You can’t attach Visual Studio debugger with SharePoint Online so to test your solution ,you can test it locally or create a site collection for testing in the SharePoint online
- Use “FXCop” to test your code if it can execute properly in SharePoint Online
- Using client object model can solve some restriction with sandbox solution like you can call external web services ,access objects from other site collections
- You can integrate SharePoint online with data stored in SQL Azure or Window Azure (integration between two cloud based services)
