The main focus will be to create a maintainable and highly testable architecture.
Following are the features of this project:

This backend is written in Typescript: The type safety at build time and having intellisense for it in the IDE like vscode is unparalleled to productivity. I have found production bug reduced to a significant amount since most of the code vulnerabilities are identified during the build phase itself.
Separation of concern principle: Each component has been given a particular role. The role of the components is mutually exclusive. This makes the project easy to be unit tested.
Feature encapsulation: The files or components that are related to a particular feature have been grouped unless those components are required in multiple features. This enhances the ability to share code across projects.
Centralised Error handling: I have created a framework where all the errors are handled centrally. This reduces the ambiguity in the development when the project grows larger.
Centralised Response handling: Similar to Error handling we have a response handling framework. This makes it very convenient to apply a common API response pattern.
Mongodb is used through Mongoose: Mongodb fits very well to the node.js application. Being NoSQL, fast, and scalable makes it ideal for modern web applications.
Redis Memcache: I have used the redis server for caching the items which does not change frequently. It will boost the performance of our system.
Async execution: I have used async/await for the promises and made sure to use the non-blocking version of all the functions with few exceptions.
Docker compose has been configured: I have created the Dockerfile to provide the easy deployability without any setup and configurations.
Unit test is favored: The tests have been written to test the functions and routes without the need of the database server. Integration tests has also been done but the unit test is favored.
A pure backend project: I have experienced that when a backend is developed clubbed with a frontend then in the future it becomes really difficult to scale. We would want to create a separate backend project that servers many websites and mobile apps.

link to postman

github

Node.js

Express.js

Typescript

MongoDB

Mongoose

Redis

Jest

Unit Testing

Docker

nodejs-architecture-blog