Debit Scheduler Take-home

Welcome! If you're reading this, odds are that you're interviewing for a backend engineering role at EarnUp. We are excited to continue the conversation! Your mission, should you choose to accept, is to build a debit scheduling endpoint for loans.

There is a lot of flexibility to this exercise... and it’s intentional. We always appreciate clean, well-documented code, but we’re also looking to see how you approach problems and make tradeoffs. We’re just as interested to discuss your design as we are to see a working app. The boilerplate code in this project should serve as a foundation; feel free to make modifications, write helper functions, extend tests, etc.

This project is designed to take 45 minutes, no more than 1 hour, but we respect your right to work on it as needed on your own time. Fork this repo to get started. Please send the recruiter a link to your solution within a week.

Deliverable

Build an endpoint called /get_next_debit that accepts information about a loan and returns the next debit amount and debit date for that loan.

There are 3 primitives to understand:

Loan - this could be a mortgage, auto loan or some other financial product that requires a reqularly scheduled payment.
Payment - a date and amount that gets paid towards a loan on the payment_due_day of the month.
Debit - a date and amount to retrieve funds from a customer. Multiple debits add up to a monthly payment.

For example, a loan with a $750 monthly payment that debits a customer bi-weekly (every other Friday) starting on May 7th, 2021 would have the following debit schedule for the month of May:

Debit $375 on May 7th, 2021
Debit $375 on May 21st, 2021

Keep in mind, some months have more debit dates than other months. The sum of debit amounts for a given month should equal the monthly_payment_amount. A debit cannot be used for a payment on the same day, it would need to be used for the next payment. Debits and payments can only occur on business days (Monday - Friday).

Explore /tests for more examples.

Example Request

{
    "loan": {
        "monthly_payment_amount": 750,
        "payment_due_day": 28,
        "schedule_type": "biweekly",
        "debit_start_date": "2021-05-07",
        "debit_day_of_week": "friday"
    }
}

Example Response

{
    "debit": {
        "amount": 375,
        "date": "2021-05-21"
    }
}

Getting Started

Run the API app

docker-compose build
docker-compose run app

The API will be exposed on 0.0.0.0:5000

Run tests

docker-compose run app python -m pytest

bonus