This is my take-home exam for the position of Back End Engineer (TypeScript) at Smartrr.

Although the stack chosen for this project is a bit too much for this specific application, I wanted to pick tools that would be applicable on a real Smartrr project (microservices, queues, etc), that is what made the biggest impact on the final decision.

• Backend

  • Postgres (database)
  • Redis (queue and message broker)
  • Nest (application framework)
  • GraphQL (entrypoint for the api)
  • Jest (testing)

• Frontend

  • React
  • Tailwind
  • Urql
  • GraphQL Codegen

The backend is composed of two different applications, which run independently of each other and communicate via a message broker (Redis).

• API

  • Handles requests from the web via GraphQL
  • Handles subscriptions via GraphQL and WebSockets (for real-time updates)

• Worker

  • Handles the conversion queue (retries, circuit breaks, paralellism, timeouts)
  • Handles the cron (runs hourly and enqueues conversions to be processed)

Below is a flow diagram that represents the entire application architecture:

1. Copy or rename the .env.example file to .env
2. Replace <YOUR_RAPID_API_KEY> with your Rapid API key inside the env file

TIP: You can do both steps with a single command:

sed 's/<YOUR_RAPID_API_KEY>/REAL_API_KEY/g' .env.example > .env

3. Run docker compose up
4. Wait for the containers to be up
5. Open http://localhost:3000

I had a great time diving into this take-home project. Really appreciate the opportunity to showcase my skills for this position. Hope you like what you see!

Cheers,

Humberto.