A full 9 hours of calls and questions.

1. An initial phone call with a recruiter, asking about skills, experience, and expected compensation.
2. A 3-hour HackerRank timed exam with 4 questions: 2 computer science and 2 practical. It included an anagram problem, K-Subarrays, and two real-world, easier problems.
3. If you pass the coding challenge, a second call with a recruiter, prepping you on "The Twilio Magic" and how they interview. They provide a PDF with details of the STAR method. This is where it becomes really obvious that Twilio is a large company with a large HR team.
4. A "Virtual On-Site" that lasts 5 hours. Each session is supposed to be 45 minutes, but they all go for an hour.

If you are the type of person who locks up while live coding for an audience, you will not do well here. These are intense tests. Get your skills up on HackerRank and be prepared for problems that are academic in nature. If you are a generalist, Twilio is probably not the place you want to interview.

The interview process included:

1. An hour of behavioral and testing practices, as well as questions about CI/CD.
2. An architecture exercise using Google Docs.
3. An hour of live coding. My example was building an LRUCache from scratch in CoderPad.
4. An hour with the hiring manager.
5. An hour with a "Bar Raiser" who asks behavioral questions.