Did the Twilio onsite for a staff SWE role in early 2026. Four rounds over two half-days on Zoom. Here's the actual structure because I couldn't find a clean breakdown when I was prepping.
Round 1: Coding (60 min) Two problems. First one medium difficulty, API/string parsing flavored. Second one harder, involved a simulation problem with state management. I got through the first cleanly and got 80% of the second. They were fine with that; the debrief later confirmed they don't expect perfect solutions at staff, they want to see how you reason and how you handle getting stuck.
Round 2: System Design (60 min) The classic. Design a scalable messaging system. I went deep on durability guarantees and the trade-offs between at-least-once and exactly-once delivery, which seemed to resonate given their actual product. I was asked to extend the design to support international routing partway through. Classic scope expansion.
Round 3: Behavioral (45 min) Competency-mapped. They asked about influencing without authority, a time I led a cross-team initiative that didn't go as planned, and what I would do differently in a past project. Standard STAR format.
Round 4: "Architecture and Vision" (45 min) This one was less common and I wasn't as prepared for it. They asked: given what you know about the CPaaS space and Twilio's position in it, what would you work on if you joined? And they meant it. They wanted to hear me have an informed opinion about the business. I talked about consolidating their product surface (Segment acquisition, deprecating legacy Programmable Voice components, etc.) and where developer tooling is heading with AI-native workflows.
Timeline: applied, OA, recruiter screen, scheduling, then the actual onsite was spread over 2.5 weeks. Debrief took another week. Total was about 5 weeks gate to decision.
Overall the panel was collaborative and they gave me context about what they were looking for after some rounds. Not hostile. The Vision round caught me off guard, so don't skip reading about their product strategy before you go in.