Intro

Welcome to the Cozero coding challenge!

Our idea is to offer you a fun and practical challenge so that we can later use it as a conversation starter to go over your thought process.

Cozero Challenge

We created a very simple MVP for an app where users can signup and list their carbon emission offsetting projects. The current functionality includes:

• Users can register/login into the app
• Users can post projects
• Anyone can see projects

Stack

• Frontend: ReactJS
• Backend: NestJS + TypeORM + MySQL.

Before run

You need:

• Node version >= 12.
• Docker

How to run

MySQL in Docker

docker-compose up -d

Backend running on port 3001

cd cozero-backend
npm i
npm run dev

Frontend running on port 3000

cd cozero-frontend
npm i
npm run dev

Requirements

We need to build upon our MVP and fix some bugs.

Improvements

• We need to be able to search for projects. Create an API endpoint that searches for projects by their title/description. The API response should be with the same fields as the listing project.

• Currently, when making a request to create a new project we can omit the listing proposal field. We need to make the field listing proposal required.

• We realized that some of the clients sometimes would mistakenly delete projects. Our clients are not tech-savvy so it would be great if we can find a way to retrieve projects that were deleted mistakenly.

Questions

• How would you make sure the emails provided from the users are real?
• After running the app for a while, we suddenly get a huge influx of new projects. We currently have over 5.000.000 projects in our database. The response time of the /projects endpoint went from 50ms to 3s. Assuming the frontend is fetching data per language and within specific timeframe (from - to date), what would you do in oder to make the app faster? E.g. request from the frontend -> GET /projects?language=${lang}&createdAtGreaterThan=${date}&createdAtLowerThan=${date}
• What else can we do in order to improve the time?
• What kind of metrics would you collect from your application to know that everything is OK?

How to submit

1. Fork this repository with private visibility and commit your changes there
2. Send an email to your hiring manager with an answer to the questions and a confirmation that you're done with the challenge. We will require you to provide access to your repository to review your challenge

What happens next

• We'll set up a follow-up call and check with you about your availability