Technical Interview Question and Answer for Junior Backend Developer (1)

Python

1. Q: What are Python decorators and how do you use them?
   • A: A Python decorator is a design pattern that allows you to modify the behavior of a function or class. It's typically used for adding functionality to existing code in a modular and readable way. Decorators are applied using the '@' symbol before a function or method.
2. Q: Can you explain the difference between lists and tuples in Python?
   • A: Lists and tuples are both sequence data types that can store a collection of items. Lists are mutable, meaning they can be modified after their creation, while tuples are immutable. Lists use square brackets [], whereas tuples use parentheses ().

Django

1. Q: What is the role of the ORM in Django?
   • A: The Object-Relational Mapper (ORM) in Django allows developers to interact with the database in a Pythonic way, by converting database queries into Python objects and vice versa. This means developers can use Python code instead of writing raw SQL queries.
2. Q: Explain the MTV (Model-Template-View) architecture in Django.
   • A: In Django, MTV stands for Model-Template-View:
     • Model: Represents the data structure. It's a Python class that maps to a database table.
     • Template: Handles the presentation layer. It's where you create the HTML files with Django template language.
     • View: Contains the business logic and interacts with the model to fetch data, which is then passed to the template.

AWS

1. Q: Describe what a VPC is and its use in AWS.
   • A: A Virtual Private Cloud (VPC) in AWS is a virtual network dedicated to your AWS account. It allows you to launch AWS resources in a network that you define. It's used for setting up a secure and isolated section of the AWS cloud to run your applications.
2. Q: How does AWS S3 work and what are its common uses?
   • A: AWS S3 (Simple Storage Service) is an object storage service that offers scalability, data availability, security, and performance. It's used for storing and protecting any amount of data for various use cases, like websites, mobile applications, backup and restore, and big data analytics.

API & Postman

1. Q: What are RESTful APIs and what principles do they follow?
   • A: RESTful APIs are application programming interfaces that adhere to the constraints of REST (Representational State Transfer) architectural style. They operate over HTTP, and their principles include statelessness, a client-server architecture, cacheability, layered system, and uniform interface.
2. Q: How do you use Postman for API testing?
   • A: Postman is used for API testing by creating and sending HTTP requests to an API endpoint. You can test various HTTP methods (GET, POST, PUT, DELETE, etc.), inspect the response, and validate the behavior of the API. Postman also allows for automated testing through scripting and collection runners.