First round is an online coding assessment, sent via email without ever talking to anyone at Circle. The assessment was fair, but I suspect there was incorrect data in the expected values of one of the test cases.

As a result I could not finish the third of 4 sections, and did not make the cut for the next phase. I have no way to contact anyone for follow-up or feedback.

To solve a coding problem via an online IDE, using the language of your choice. The problem was broken into 4 parts, you had to incrementally enhance the solution in each part and all test cases have to run and pass before you can move to the next part.