A ServiceNow integration is an information exchange between the ServiceNow Platform and another system or source.

Inbound integration is making call from third party application to ServiceNow's REST API to get information from ServiceNow, or create/update records.

Note : If asked, you would need to explain practical inbound integration that you have implemented

Outbound integration is making calls from ServiceNow to other applications API to get information or create/update records.

Note : If asked, you would need to explain practical outbound integration that you have implemented

A management, instrumentation, and discovery (MID) Server is a Java application that runs on a server on your local network. MID Servers facilitate communication and data movement between a single ServiceNow® instance and external applications, data sources, and services.

A mid server sits inside firewall, collects information from infrastructure CIs, then puts that info out in the cloud in ServiceNow instance.

Below is the graphical representaion which illustrates working of MID server :

ServiceNow instance is hosted in the cloud. It can connect to other cloud based systems to share data etc, however your internal network is likely not wide open to connections from external systems. So the MID server acts as connection between your internal network and the ServiceNow instance.

It can be used to send Discovery data that it collects on your network to the ServiceNow instance. It can also allow ServiceNow to connect to data sources that are on your network (like SQL servers, internal APIs etc)

There are 5 basic http methods which are as follows,

GET : Retrieves information.

POST : Creates new records.

PUT : Updates the partial or specific records, it checks if resource exists then it will update the record or else it creates record.

PATCH - > Updates record.

DELETE : Deletes record.

POST is used only to create records whereas PATCH is used to only update the record while PUT is kind of combination both where if record exist then it will update the record otherwise it creates new one.

OAuth is an open standard for token based authontication. It allows user access instance resources by obtaining Token rather than entering login credentials with each resource request.

Table API allows us to perform create, read, update, and delete (CRUD) operations on existing tables.
The Import set API allows us to interact with import set table.

ServieNow's REST API explorer is an application to construct and test API requests to a ServiceNow instance. The REST API explorer is available to users with the rest_api_explorer role or admin role.

We can write server side script by using below REST API class.
sn_ws.RESTMessageV2('rest_message_name','method_name');
Later we can use methods provided by above class to perform further operation.

The scripted REST API feature allows application developers to build custom web service APIs.
We can define service endpoints, query parameters, and headers for a scripted REST API, as well as scripts to manage the request and response.

1. SOAP stands for Simple Object Access protocol whereas REST stands for REpresentational State Transfer.

2. REST has SSL and HTTPS for security, on the other hand SOAP has SSL and WS security due to which in the cases like Bank account password, Card number etc. SOAP is preferred over REST.

SOAP allows only XML format REST allows other format as well e.g. JSON, XML.

4.SOAP requires more bandwidth REST requires less bandwidth.

5. Uses the envelope type of messages where message details are secured, REST uses kind of postcard where URI exposes the business logic.