Meta's 45‑minute design loop
Jacob Bartlett posted a step‑by‑step, non‑technical breakdown of Meta's 45‑minute system design interview — scoping, requirements, high‑level design, deep dive, and wrap‑up — with timing for each phase. He also recommends practicing on tools like Excalidraw to mirror Meta's whiteboard cadence. (x.com) (x.com)
Prep guides that map Meta’s 45‑minute design round converge on a time split: roughly 5 minutes for introductions/scoping, 10–15 minutes for requirements and high‑level architecture, ~15–20 minutes for a deep dive on one component, and 5 minutes to wrap up. (tryexponent.com) Meta typically assigns 1–3 system‑design or product‑architecture interviews during onsite loops for L4+ candidates, with each design round slated at 45 minutes for roles like software engineer and product‑facing engineers. (igotanoffer.com) Excalidraw is the de‑facto whiteboard tool cited in multiple preparation guides and company advisories; prep packs and reusable Excalidraw symbol libraries have emerged to shave seconds off diagramming during the timed cadence. (tryexponent.com) Commercial courses and Meta‑focused curricula emphasize quick ballpark SRE calculations (QPS, storage, bandwidth), heatmap traffic estimates, and drilling a single API/data model or cache strategy during the deep‑dive phase. (educative.io) Jacob Bartlett has published analysis of Meta’s iOS/system‑design interviews in his “Jacob’s Tech Tavern” Substack (including an “Inside Meta’s ‘iOS System Design’ Interview” post dated Nov 25, 2025) and lists ~9.1K subscribers on his Substack profile. (blog.jacobstechtavern.com) Prep authorities warn that inability to organize tradeoffs under 45 minutes is a leading failure mode in Meta loops, and they recommend timing mock interviews to the same phase breakdown used by Meta interviewers. (tryexponent.com)
