Running a coding interview? Send one link to a shared editor that runs the code

What to know

The question is chosen because it fits a 45-minute slot and shows a lot: the candidate has to see that sorting by start makes the problem linear, decide whether touching intervals merge, and handle the empty list. The five test cases cover overlap, touching ends, unsorted input, an interval that swallows the others, and empty input. A correct sort-and-sweep answer passes all five in well under a millisecond; the starter returns the input unchanged, so it starts at 1/5.

For the candidate the setup cost is zero: one link, no account, no download, any modern browser. Code runs in a sandbox in their browser, not on a server, and the output is written into the room so you see exactly what they see, labelled with who ran it and how long it took. A loop that never ends is stopped after five seconds without freezing either tab, which matters when someone is nervous and experimenting.

Supported languages for running are JavaScript, TypeScript (types are stripped, not checked) and SQL on an in-browser SQLite. Python, Java, Go and other languages can be written and discussed but do not run here, so for an interview that requires executing Python, use a tool with that interpreter. Files in the room cannot import each other, so keep each question self-contained in one file.

Everything in the free room is visible to everyone in it, including question.md, and a free room holds 3 people at once and 2 files, which fits one interviewer, one candidate and an observer. Pro ($29 once, no subscription) adds the parts interviewers need every week: notes and a scorecard stored under your account that the database rules refuse to show anyone else, a question bank to start a fresh room from a saved question in one click, a lock so only you can edit after the interview, keystroke replay, rooms of up to 10 people with unlimited files, .zip download, and rooms that never expire.

Updated October 8, 2026 · Cosmovex