This is a take-home coding exercise used to help evaluate and work with candidates looking to join the team at Change.org. The general idea is for candidates to complete the challenge before the engineering interview. During the interview we will use the code as a discussion point.
You can submit the code by providing a pointer to a source control repository. In your submission, you should include:
- The code (include all relevant files).
- A small README documenting any assumptions or simplifications you have made, and a link to the working website.
Snacky Snacks has hired you to develop their payment processing web page. They believe an online store will be the best way to buy snacks by weight.
| Snack | Cost per Kg |
|---|---|
| Chocolate | $5.60 |
| Dark Chocolate | $6.00 |
| Bubble Gum | $2.00 |
| Cotton Candy | $1.50 |
Snacky Snacks has decided to use Stripe as their payment processor. They started researching a bit about how to get started with Stripe, and this is what they found.
The following features must be part of your final submission.
- The user must be able to pick the type and weight of the snack.
- Payments must be processed using Stripe. See here for more details.
- The user must be able to clearly see any errors that occur while submitting the payment.
- Aim for the best possible user experience (clear user interface, minimal number of clicks, fast loading, etc).
The following features are not mandatory, but they will add bonus points.
- Let the user charged by the payment processor using multiple currencies; the cost of each snack stays equivalent for all currencies.
- Make the website responsive.
- Live validation of credit card field (see Stripe validation library or use Stripe Elements).
- Allow users to sign up for monthly snack plans; the users should automatically be charged monthly by the payment processor.
- Implement anti-fraud measures (we'll let you come up with what these can be).
The following features are not mandatory and more challenging. However, these are not expected to be implemented by most candidates.
- Add unit tests for your code.
- Add SEPA as an alternate payment method.
- Let user pay with Google Pay, Microsoft Pay, and Apple Pay using the Stripe Payment Request Button
- Ability to process payments using Braintree.
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Payment Processor A payment processor is a company appointed by a merchant to handle transactions from various channels such as credit cards. Examples: Stripe, Braintree
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Stripe Stripe is a payment processor with software that allows individuals and businesses to make and receive payments over the Internet. Stripe provides the technical, fraud prevention, and banking infrastructure required to operate online payment systems.
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Braintree Braintree, a division of PayPal, is a company that specializes in mobile and web payment systems for e-commerce companies.
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Is it OK to share your solutions publicly?
You do the work, you own the code. Given we are asking you to give up your time, it is entirely reasonable for you to keep and use your solution as you see fit.
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Should I do X?
For any value of
X, it is up to you, we intentionally leave the problems a little open-ended and will leave it up to you to provide us with what you see as important. -
Something is ambiguous, and I don't know what to do?
The first thing is: don't get stuck. We really don't want to trip you up unintentionally, we are just attempting to see how you approach problems. That said, there are intentional ambiguities in the specification, partly to see how you fill in those gaps.
If you really feel stuck, our first preference is for you to make a decision and document it with your submission - in this case there is really no wrong answer. If you feel it is not possible to do this, just send us an email and we will try to clarify or correct the question for you.