Risk Score API

Running the API:

Requirements:

• Docker CLI

Step 1 - Build the docker image:

Run the following command on the root of the project to build the docker image

$ docker build . -t risk-score-api

Step 2 - Start the docker container:

Replace PORT with the port you want the API to listen to and run the following command to start the docker container with the application

$ docker run -p PORT:8080 -d risk-score-api

Available endpoints:

POST /api/risk - Calculate the risk profile for a client based on his/hers information

• Expected payload:

  {
    "age": 35,
    "dependents": 2,
    "house": { "ownership_status": "owned" },
    "income": 0,
    "marital_status": "married",
    "risk_questions": [0, 1, 0],
    "vehicle": { "year": 2021 }
  }

  details on the payload structure can be found on this repo

• Expected response:

  {
    "auto": "regular",
    "disability": "ineligible",
    "home": "economic",
    "life": "regular",
    "renters": "ineligible",
    "umbrella": "economic"
  }

  details on the response structure can be found on this repo

Running the API for local testing and development:

Requirements:

• Node.js 14 (or higher)
• Yarn

Step 1 - Install the dependencies and build the project:

Run yarn on the root of the project to download the dependencies and build the project

$ yarn

Step 2 - Start the API:

Run the start:dev script to start the API, watch for changes(and restart the API when they happen) and expose a port to debug the code. It's possible to debug the code on VSCode with the provided launch.json file

$ yarn start:dev

Tests:

All the tests can be listed by running

$ yarn test:list

To watch for changes and run the related tests the following script can be used

$ yarn test

Adding new Risk Rules to the algorithm:

The risk algorithm is based on a collection of rules that can be found on the rules folder. All the rules listed on the rulesList will be applied to the client's information to provide a final RiskScore, that in the end is converted into the client's RiskProfile.

To add a new rule to the algorithm all you need to do is to export a new function(following the RiskRule interface) from a new file under the rules folder with the rule name, import the rule into the index.ts and add it to the rulesList.

Technical decisions made:

Choosing Node.js and express over anything else:

My choice was basically out of affinity, I had done lots of work previously with Node.js APIs and was confident that I could structure a good new API from scratch in sufficient time.

Choosing Typescript over Javascript:

Type consistency gives me more confidence on my code and helps a lot during development because of the autocompletion that is enabled by having it.

Choosing Docker for building and running the API:

Docker gives me confidence that the code will be built and run succesfully anywhere else it needs to (as long as Docker is available).