Did the Webflow take-home and then the live coding round this spring. Writing this up because I could not find a straight answer on what format they use before I went in.
The online assessment is NOT a generic LeetCode platform. They use a custom environment that's closer to a real IDE. You get a problem with a small codebase attached and have to add a feature or fix a bug. The problem I got was roughly: given a simplified version of a style inheritance model (think: cascading CSS properties across nested components), implement a resolver that correctly applies overrides at each level.
So it's definitely not "sort this array" LeetCode stuff. You're reading code, reasoning about a tree structure, and writing something that fits into an existing pattern. TypeScript was available, which I used.
Difficulty: I'd call it medium-hard in terms of conceptual complexity, but the algorithmic piece was more graph traversal than dynamic programming. The real challenge was reading and understanding their existing structure quickly.
Live coding round (later in the loop) was more traditional. Two 45-minute problems. One was a hashmap/string problem, one was a tree problem. Both were medium difficulty by LeetCode standards. The interviewers were collaborative, not silent watchers.
A few notes: Code quality mattered. They called out variable naming and asked about testing during the debrief. They want you to talk through your approach before diving in. I almost skipped that step and the interviewer gently redirected me. Time management was tighter than I expected. 45 minutes goes fast when you're explaining as you go.
Overall the bar felt like a solid mid-to-senior level, not a grind-leetcode-hards shop.