what are the advantages of using CSOM over SSOM in SharePoint ?

Client Side APIs refer to the Client Object Model that was introduced in SharePoint 2010. There are basically 3 "flavors" of the Client Object Model: .NET, Silverlight and JavaScript (ECMAScript) The Main advantage of the CSOM is that you do not need to be on the Server to use them in your program. The .NET client object model can be used in any Desktop or Web Client. The Silverlight CSOM can be used in silverlight applications (doh!) and you can call the JS Client Object Model directly from your web pages. 45 down vote 2013 Model Types: CSOM: Client-side object model. C# (or Visual Basic) only, use NuGet, at the moment same package for both 2010 and 2013. JSOM: JavaScript object model. JavaScript only. SP.ClientContext.get_current() for normal use. new SP.ClientContext('url...') for specific SPSite. Note this works cross-SPSite in 2013. SSOM: Server-side object model. C# (or Visual Basic) only, use Microsoft.SharePoint (15) DLL. Must be deployed on same farm. REST: REST web technologies and standard Open Data Protocol (OData) syntax. Either JS (JavaScript) or C# (or Visual Basic) helper package in NuGet. Hosting: SharePoint hosted: JavaScript and templates only. By templates I mean list templates, content types, etc. Anything that can be uploaded to the SharePoint virtual file system can also be added, such as .aspx-pages. Autohosted: C# (or Visual Basic) only. Currently only supported on Office 365. On app purchase an Azure instance will be automatically provisioned. Uses OAuth to comunicate to SharePoint site. Provider hosted: C# (or Visual Basic). Similar to Autohosted, but is meant to be hosted more manually (i.e. On Azure). So you fire up a web application, on any server, and then use S2S to connect to SharePoint. Sandboxed: Remnant from 2010, can be uploaded to Solution gallery. Support for limited subset of the SSOM. No file access, so can not deploy anything to _layouts folder. If you use the limited SSOM-part (C#) your solution will be considered deprecated. Support for templates such as list templates and content types, deployed directly to host web. Farm solution: Full access, deploy through PowerShell. Technologies table: +--------------------------------------------------------+ ¦ ¦ CSOM ¦ JSOM ¦ SSOM ¦ REST JS ¦ REST C# ¦ ¦---------------+------+------+------+---------+---------¦ ¦ JavaScript ¦ ¦ x ¦ ¦ x ¦ ¦ ¦ C# ¦ ¦ ¦ x ¦ ¦ x ¦ ¦ From browser ¦ ¦ x ¦ ¦ x ¦ ¦ ¦ From server ¦ x ¦ ¦ x ¦ ¦ x ¦ ¦ OAuth2 ¦ x ¦ x ¦ x ¦ x ¦ x ¦ ¦ S2S ¦ x ¦ ¦ x ¦ ¦ ¦ +--------------------------------------------------------+ Hosting table: +---------------------------------------------------------------------+ ¦ ¦ CSOM ¦ JSOM ¦ SSOM ¦ REST JS ¦ REST C# ¦ ¦---------------------+------+------+-------------+---------+---------¦ ¦ SharePoint hosted ¦ ¦ x ¦ ¦ ¦ ¦ ¦ Autohosted ¦ x ¦ ¦ ¦ ¦ x ¦ ¦ Provider hosted ¦ x ¦ ¦ ¦ ¦ ¦ ¦ Sandboxed solution ¦ x ¦ x ¦ x(limited) ¦ x ¦ x ¦ ¦ Farm solution ¦ x ¦ x ¦ x ¦ x ¦ x ¦ +---------------------------------------------------------------------+ 2010 Model Types: CSOM: Client-side object model. C# (or Visual Basic) NuGet and JavaScript. SP.ClientContext.get_current() for normal use. new SP.ClientContext('url...') for specific SPWeb. SSOM: Server-side object model. C# (or Visual Basic) only, use Microsoft.SharePoint (14) DLL. Must be deployed on same farm. REST: REST in 2010 is only for ListData.svc. Note that SPServices (jQuery plugin) utilizes the .asmx services in _/vti/bin , such as /_vti_bin/Webs.asmx Technologies table: +-------------------------------------+ ¦ ¦ CSOM ¦ SSOM ¦ REST ¦ ¦---------------+------+------+-------¦ ¦ JavaScript ¦ x ¦ ¦ x ¦ ¦ C# ¦ x ¦ x ¦ x ¦ ¦ From browser ¦ ¦ x ¦ x ¦ ¦ From server ¦ x ¦ x ¦ ¦ +-------------------------------------+ Hosting table: +---------------------------------------------------------------------+ ¦ ¦ CSOM ¦ JSOM ¦ SSOM ¦ REST JS ¦ REST C# ¦ ¦---------------------+------+------+-------------+---------+---------¦ ¦ Sandboxed solution ¦ x ¦ x ¦ x(limited) ¦ x ¦ x ¦ ¦ Farm solution ¦ x ¦ x ¦ x ¦ x ¦ x ¦ +---------------------------------------------------------------------+ read less

SharePoint provides different classes to interact with SharePoint, they are known as object model class. They might be Server object model or Client object model. We can use the server object model if our code is running on the server side, on one of your SharePoint front end. We can use the client object model if our code needs to run on a different machine from the front end SharePoint Key Points one should know about the CSOM: 1) The Main advantage of the CSOM is that you do not need to be on the Server to use them in your program. The .NET client object can be used in any Desktop or Web Client. The Silverlight CSOM can be used in silverlight applications and you can call the JS Client Object Model directly from your web pages. 2) No Compilation required as required on the server side, NO IISRESET required. 3) Web parts with rich user interface can be developed with the help of Silverlight and jQuery COM can be implemented using 3 client API's 1. .NET managed application (Console application/Windows Forms Application) 2. Silverlight application 3. ECMAScript (JavaScript, JScript) The following table shows the equivalent objects that the new APIs provide for common SharePoint Foundation 2010 server objects. Server Object Model .Net Managed & Silverlight JavaScript SPContext ClientContext SP.ClientContext SPSite Site SP.Site SPWeb Web SP.Web SPSite.Title Site.Title SP.Site.get_title() & SP.Site.set_title() read less

If we talk about advantages of CSOM only... 1. CSOM runs on client browser which reduces the burden on server. 2. Rich UI can be developed with the help of jQuery/HTML/CSS easily. 3. Can easily be integrated with third party jquery libraries. 4. Any HTML/javascript knowledge is sufficient to work on CSOM 5. Multiple development options(.NET/Silverlight/JSOM). 6. No SharePoint Server installation required. read less

There are plenty of Advantages and couple of disadvantages as well. Advantages are 1) We can utilize client side computing by using CSOM. 2) Client side processing is little faster when compared to Server side due to distributed computing where client only processes how to displays the data and server only processes the request to server the data. 3) Using CSOM we can use any type of client side framework like JQuery, AngularJS, KnockoutJS to render the UI. 4) At any moment if the UI has to be changed in CSOM model, we dont need to update whole solution and deploy all we can do is just updating the UI design in the form of HTML. 5) CSOM gives us the flexibility to design out UI Application to use any client device like IPhone, IPad, Tablets, Mobile Phones. 6) CSOM gives us more flexibility and control for using SharePoint 2013 App model for developing Apps. There are plenty of other advantages also which can be understood once we start learning them step by step. read less

CSOM = all three implementations, .NET, Silverlight and JavaScript. JSOM = just the JavaScript implementation .NET CSOM = just the .NET implementation please read below link https://channel9.msdn.com/Series/Reimagine-SharePoint-Development/Understanding-the-differences-between-Server-Side-Object-Model-and-the-Client-Side-Object-Model read less