Did the Squarespace coding rounds last month while employed. Here's what actually happened because the prep guides I found were all old.
There were two coding rounds back-to-back in the onsite (or virtual onsite, in my case). Each was 45 minutes with a different interviewer.
Format: HackerRank environment shared over video call, you code live while talking. No pre-submission OA before the interviews from what I could tell, at least not for the senior SWE track. Might be different for new grads.
Difficulty: Leetcode medium, consistently. One problem per round. Neither problem was a trick question or an obscure algorithm. One was a string/parsing problem, the other involved a graph traversal. I finished each with roughly 10-15 minutes left and spent that time on edge cases and a brief complexity walkthrough.
They're not looking for you to solve Leetcode hard problems in 30 minutes. That's not the signal they're after. What mattered: could I talk through my thinking clearly, identify edge cases on my own (they waited to see if I caught empty input before they mentioned it), and write reasonably clean code.
Language choice: Python or Java seemed fine. I used Python, no friction.
One thing that stood out: both interviewers asked follow-up questions after the solve, like "how would this change if the input size were 100x" and "what would you test first." It's not purely an algorithm speed test.
For calibration: I'm 7 YOE backend, hadn't seriously leetcoded in two years, did maybe 2 weeks of mediums before this. That was enough. If you're spending six months grinding Leetcode hard for Squarespace, that's probably overkill for the coding rounds specifically.