1. Difference between javascript and nodejs?

NodeJS : NodeJS is a cross-platform and opensource Javascript runtime environment that allows the javascript to be run on the server-side. Nodejs allows Javascript code to run outside the browser. Nodejs comes with a lot of modules and mostly used in server-side.

JavaScript : Javascript is a high-level,multi-paradigm programming language. that is used for writing scripts on the website. it's capable enough to add HTML and play with the DOM. Mainly used on clientside.

2. When should you use nodejs and when should you use mongodb?

MongoDB is the Document Oriented Database. MongoDB stores a lot of data in JSON format. MongoDB's performance is much faster than any RDBMS. MongoDB is designed to work with Large Scale Data. MongoDB can work on multiple servers. MongoDB can handle a large number of access requests easily. There are 2 design patterns in programming. One is asynchronous programming and the other is synchronous programming. Node JS by default follows the Asynchronous pattern. That is, it does not wait for a task to be completed. In the meantime, NodeJS started another job. That's why we use nodeJS.

3. Differences between sql and nosql databases?

SQL databases are relational, NoSQL databases are non-relational. SQL databases use structured query language and have a predefined schema. NoSQL databases have dynamic schemas for unstructured data.SQL databases are vertically scalable, while NoSQL databases are horizontally scalable.

4. What is the purpose of jwt and how does it work?

JWT is an open standard used to share security information between two parties — a client and a server. Each JWT contains encoded JSON objects, including a set of claims. JWTs are signed using a cryptographic algorithm to ensure that the claims cannot be altered after the token is issued.