I want to integrate eLearning to an existing system that I already have, I have been reading a lot about two standards SCORM and xAPI but all what I read was theoritical differences about pros and cons of each standard, anyhow I want to have a technical differences from a developper perspective about implementing those standards in the system, what are the differences by implementing those standards from a developping view?i Just want headlines of the process of developping those standards. any references or documentation about that would also be very helpful. and would it be doable or logical to integrate one standard in the system and later on integrate the other one? for example SCORM then later if needed I integrate xAPI?
Let me start with the integration part. Yes you can do SCORM and later integrate xAPI, though that might require retooling the SCORM course, or LMS to do the xAPI part. This is done in practice. A lot of what I do is integrate existing SCORM ecosystems with xAPI and LRSs.
As for differences in SCORM and xAPI, here's some high-level info.
SCORM is a set of specifications that defines the way to package content, the way to have your content report data, and the way an LMS launches and manages SCORM content and data. xAPI is a specification that defines a REST style API and JSON data format to track interactions/activity that happened in content.
As Andrew said, SCORM content finds an embedded API object in the browser DOM and uses that to communicate very structured and specific data to an LMS. xAPI uses a REST HTTP API to communicate various data in a well defined format.
Without some creative programming, SCORM typically is content that is delivered via a browser from a Learning Management System to the client. Typically that is in the form of HTML, images, videos. xAPI can be those types of things as well but since the API is HTTP/REST-like, the support of unmanaged content - simulators, phone apps, games - is a little easier.
SCORM's data model is very clearly defined in the specification and not normally extended. xAPI's data format is defined, but the actual data is much looser and open to the needs of the developer.
SCORM has been around since about the year 2000 in various versions. It is well supported in LMSs and content development tools. And many in the eLearning space know it. xAPI is newer. Support is growing as well as the number of folks who understand it, but it is still less supported than SCORM.
One final thing of note, SCORM specs never defined a way to get data out of the LMS once the SCO attempt has ended. This made reporting and metrics difficult to do without getting the LMS vendor to build those features in. xAPI defines a GET endpoint to retrieve data (This might not be performant when you might have 100ks to millions of data points, but you can get the data back out - caveats about permissions aside) Some LRS vendors do add reporting and analytics platforms, as well as some adding ways to get your data into BI or data analysis tools.
There's more you'll find as you get into the space but that's some of the things off the top of my head.
I would recommend you read the xAPI spec first mainly because it is more easily consumed. Then look at SCORM - it has different versions (1.2, 2004 2-4th editions).
As for implementing content,
Looking at the specs is the driest but the authoritative way to learn about the different specs. There are also some very good articles and videos out there by various vendors and implementors.