Finished my AT&T software engineer interview process last month so figured I'd document it while it's fresh. This was for a mid-level SWE role on one of their 5G platform teams in Dallas.
The whole thing took about 5.5 weeks from first recruiter contact to offer. Here's how it broke down:
Recruiter screen (week 1): About 30 minutes. Standard stuff. She asked about my current stack, why I was interested in telecom, and whether I was open to hybrid (3 days onsite in Dallas). No technical questions here.
HackerRank online assessment (week 2): 90 minutes, 3 coding problems. Two medium-level problems (one on strings, one on graphs) and one SQL question. I thought the SQL would be trivial but it was a multi-join aggregation with a window function. Probably the hardest part of that section.
Technical phone screen (week 3): 45 minutes with a senior engineer. He started with about 10 minutes of resume questions, then gave me a medium-level coding problem. It was a sliding window variant. He let me talk through it before I coded, which felt intentional. Wasn't a race.
Onsite / final round (week 5): Four back-to-back video calls over one day (virtual onsite). Two coding rounds, one system design, one behavioral with the hiring manager. Coding was leetcode medium level, nothing crazy. System design was infrastructure-flavored: something about designing a notification delivery system at scale, which makes a lot of sense given they're an actual carrier.
Overall: the process felt a little slower and more bureaucratic than FAANG, which I expected. Interviewers were uniformly nice and not adversarial. The system design interviewer was clearly senior and asked sharp follow-up questions but wasn't trying to trip me up.
Got an offer. Total comp was lower than I'd get at a pure tech company for the same level, but the role had stability appeal and the RSU cliff is only 1 year.
Happy to answer questions.