Technical assessment: Backend Developer - SaaS To Do list API

Objective

Develop a RESTful API for a SaaS-based "To Do List" application that allows users to manage tasks. The API must include full CRUD operations, user authentication, and multi-tenancy support. Additionally, the application should be containerized using Docker for easy deployment.

Requirements

1. Core features

• User authentication: Implement user registration and login functionality. Each user should have their own workspace to manage tasks.
• Multi-Tenancy: Ensure that tasks are isolated per user (i.e., User A cannot see User B's tasks).
• CRUD operations on tasks:
  • Create task: Users can create a task with a title, description, and status.
  • Read tasks: Users can retrieve a list of all their tasks or a specific task by its ID.
  • Update task: Users can update the title, description, or status (completed/not completed) of a task.
  • Delete task: Users can delete a task by its ID.
• Task sharing: Implement a feature where users can share tasks with other users. Shared tasks should appear in both users' task lists.

2. Middleware

• Implement a middleware that logs every incoming request. The middleware should capture:
  • The requested URL.
  • The HTTP method used.
  • The timestamp of the request.
  • The execution time of the request.
• Implement any other needed middleware.
• Optionally, extend the middleware to log the authenticated user’s ID and the user’s role (e.g., admin, user).

3. Docker

• Create a Dockerfile to build a Docker image for the application.
• Create a docker-compose.yml file that sets up the application, including any required services such as the database.
• Ensure the application can be fully run within Docker containers.

4. SaaS considerations

• Subscription plans: Simulate different subscription tiers with varying levels of access (e.g., free plan with a limit on the number of tasks, premium plan with unlimited tasks). This can be implemented using feature flags or a simple conditional check based on the user's plan.
• Rate limiting: Implement rate limiting for API requests based on the user's subscription plan.

Technical specifications

• Language & framework: You may use Node.js (Express or Fastify).
• Database: Preferably use a relational database such as PostgreSQL or MySQL, but other databases are acceptable.
• Authentication: Implement authentication using JWT (JSON Web Tokens) or session-based authentication.
• Testing: Include unit tests for key functionalities.
• Documentation: Provide clear documentation in a README.md file, including instructions on how to set up, run, and use the application both locally and in Docker.
• Evaluation bonus: You can implement any other feature or improvement (e.g: basic frontend application, postman file to test endpoints, file attachment to the task, etc.)

Deliverables

1. Source code:

• Push the complete source code to a private GitHub repository.
• Include the Dockerfile and docker-compose.yml.
• Ensure the repository is well-structured and the code is clean and organized.

2. Documentation:

• Include a README.md file with:
  • A description of the project.
  • Setup and installation instructions.
  • API usage examples.
  • Instructions for running the application in Docker.
  • Notes on middleware, subscription plans, and rate limiting.

Submission deadline

You have 7 days from the date of assignment to complete the assessment and push it to GitHub.

How to submit

• Create a private repository on GitHub.
• Notify us via email once you have completed the assessment with the link to the repository.