What does a technical interview at a big tech company involve?

A typical loop is a recruiter screen, one or two technical phone screens, then an onsite of four to six rounds mixing coding, system design and behavioural. The exact shape varies, but the components are fairly standard across large technology companies. **The rounds:** 1. **Recruiter screen (30 min).** Background, motivation, logistics, salary expectations. Non-technical but not a formality — be prepared with a clear summary of your experience and a researched salary range. 2. **Technical phone screen (45-60 min).** One or two coding problems in a shared editor. Data structures and algorithms. The bar is usually solving it with a reasonable approach while communicating clearly. 3. **Onsite / virtual loop (4-6 rounds):** - **Coding (2-3 rounds).** Medium-difficulty algorithmic problems. Arrays, hash maps, trees, graphs, two pointers, binary search, sometimes light dynamic programming. - **System design (1-2 rounds, more for senior roles).** Design a scalable system — a URL shortener, a news feed, a chat service. For junior roles this may be absent or replaced by a practical design discussion. - **Behavioural / values (1 round).** STAR-format questions about conflict, failure, leadership, ambiguity. At some companies this round carries real weight and can sink an otherwise strong candidate. - Sometimes a **domain round** (frontend, mobile, data) or a practical debugging exercise. **What they're actually scoring**, which matters more than getting a perfect answer: - **Communication.** Do you clarify requirements, explain your approach, think out loud? Silent brilliance scores badly. - **Problem-solving process.** How you handle being stuck, whether you take hints well, whether you test your own code. - **Code quality.** Reasonable names, structure, handled edge cases. - **Trade-off reasoning**, especially in design rounds. There's no correct architecture; they want to hear you weigh options. **Preparation priorities**: pattern-based practice over volume, at least a few full mock interviews out loud, and — if you're mid-level or above — genuine system design preparation, because it's the round most people neglect and it's frequently what separates offers from rejections. **One practical note**: rounds are usually scored independently and combined by a committee that never met you. A weak round isn't necessarily fatal, so if one goes badly, reset completely before the next. Candidates who spiral after a bad round lose rounds they would have passed — and interviewers do notice a candidate who recovers well.