Did my Perplexity onsite in May 2026 for a security engineering role. Four rounds back to back, virtual, about 4.5 hours total with breaks. Here's the structure as I experienced it.
Round 1: Coding. 45 minutes, one problem. For my role it was a parsing and state-tracking problem (network log analysis). Medium-hard. They cared a lot about how I structured the code, not just whether it ran.
Round 2: System design. 60 minutes. Given it was a security role, I got a question about designing an anomaly detection pipeline for API traffic at scale. Classic for security-flavored SD. I talked through stream processing, baselining, alert thresholds, reducing false positives. They pushed on storage and query efficiency for historical data. Solid conversation.
Round 3: Domain knowledge. This was specific to security. Application security concepts, threat modeling, how I'd assess a new third-party integration for risk. Felt like a seasoned security engineer asking real questions, not a checklist.
Round 4: Hiring manager / values conversation. More conversational, the behavioral stuff came up here. See other posts for specifics on what kinds of questions.
Pacing was tight. Little downtime between rounds. The interviewers were well-prepared, had my resume, and the questions were connected to what I'd said in earlier rounds. One person mentioned something from my coding round answer in the design round, which was a good sign they're actually comparing notes.
Total loop from OA to onsite decision: about 3 weeks for me. Some people seem to get it faster. Decision came back in 4 business days after onsite, not the "we'll have feedback in 5-7 business days" void that usually means rejection.
Overall: harder than most mid-size tech companies I've interviewed at, lighter than Google or Amazon full loop. Felt genuinely meritocratic.