Applied to a senior backend role at T-Mobile in February. Heard back in about 10 days, which was faster than I expected for a big telecom. Here's the actual sequence: Recruiter screen (30 min, pretty standard, she was nice, asked about comp range early which I appreciated) Hiring manager call (45 min, mostly behavioral, a few tech architecture questions about distributed systems) CodeSignal OA, 70 minutes, two coding problems, medium difficulty. One was basically a graph traversal, the other was string manipulation. Totally doable. Virtual panel, 4 rounds back to back on Zoom. Behavioral, system design, another behavioral, and then a "culture fit" with a senior director that was more of a casual chat.
The behavioral stuff is serious here. Not just "tell me about a time you failed." They want to see how you tie outcomes to the Un-carrier values. I hadn't prepared for that specifically and it cost me in at least one round. Interviewers were referencing "Un-carrier" in their questions directly. Would've been nice to know that going in.
System design was solid. Microservices, API gateway design for high-throughput, they know what they're doing technically. Not a gotcha exercise.
Offer came 3 weeks after the panel. Total process was about 7 weeks start to finish. I ended up not taking it (comp was slightly below my target for a Bellevue cost-of-living adjustment), but the interview experience itself was actually pretty good.