One of the ongoing pain points that ServiceNow developer run into is staying abreast on information about the various server side and client side APIs. It can take some thought to remember which API is occuring in the browser vs the server. That can be compounded even more by the complication of which server side APIs are global vs scoped, and then which version they were introduced or their scope access was altered. There is an API section on the Developer Portal but this is a complicated set of data that is not easy to represent in an HTML table.
There is now some help on this front. Available now is the API Matrix. It is a downloadable Excel spreadsheet packed full of information about ServiceNow APIs. There are lists of classes and all their public APIs, listed by applicable stage, version, and scoping access. There are pages within the workbook of all the REST APIs available, only the scoped APIs. etc. There are suggestions for workarounds for global APIs when a scoped alternative is available. If you are running into problems with lack of information on this topic, that problem has flipped. There is so much information here, you can easily lose a lot of time digging through it.
In order to access this file, log on to the Developer Portal. Under the same menu that houses the various API links, you’ll find a link to download this file. Once you have it downloaded, you can slice and dice, search and filter and dig through for the information you want. Happy parsing!