I'm a Software Engineer (SDE-3) at Walmart Global Tech with 4+ years of experience, and I've sat on both sides of the interview table — as the candidate and as the interviewer. I've solved 3000+ DSA problems across coding platforms, and I've been through most of the common LLD patterns — so in a mock session, I'm not figuring things out alongside you. I already know the approach, the traps, and what a strong answer actually sounds like.