Twilio | Senior Software Engineer | Dublin, Ireland
- Location
- Dublin, Ireland
- Posted
- 11 May 2026
Summary
Interview process included HR screening, hiring manager round, asynchronous task scheduler exercise, system design, and director behavioral round. Rejected despite positive feedback during interviews.
How it went
Recently interviewed with Twilio for a Software Engineer role. Sharing a concise overview of the process since it was quite different from the usual DSA-heavy interviews.
- HR Screening: Basic discussion around experience, projects, and “Why Twilio?”
- HM Round: Mostly behavioral + deep dive into past experience and ownership.
[If you pass the above two, then only the below rounds are scheduled]
- Programming Exercise: Asked to implement an asynchronous Task Scheduler. Surprisingly, it was not LeetCode-style at all despite what the recruiter initially mentioned.
- Screen sharing was required
- Googling/documentation lookup was allowed
- Heavy focus on implementation and concurrency concepts
Honestly, this round caught me off guard, but somehow managed to navigate through it. The interviewer even mentioned they hadn’t seen many people complete all the test cases, which felt good to hear. - System Design Round: Discussion around designing systems related to SMS APIs / communication infrastructure.
This guide was super helpful during preparation:
Twilio System Design Interview Guide - Director Behavioral Round: Standard leadership and behavioral questions.
Verdict
Rejected ❌
Honestly, not entirely sure what went wrong because all the interviewers seemed quite happy with my performance, especially during the programming round.
Questions asked (2)
- 01
Asynchronous Task Scheduler
Data Structures & Algorithms · Hard
Implement an asynchronous Task Scheduler that supports scheduling tasks to run after a specified delay or at recurring intervals. The implementation should handle concurrency properly, ensuring thread safety when adding, canceling, or executing tasks. Candidates were allowed to look up documentation and use online resources during screen sharing.
- 02
SMS API System Design
System Design
Open the problemDesign a scalable system for handling SMS APIs and communication infrastructure similar to Twilio’s offerings. Topics likely included rate limiting, message queuing, fault tolerance, scalability patterns, and third-party integration strategies.
How they prepared
I referred to a system design handbook specifically focused on Twilio's interview process which helped in understanding how to approach their system design questions. For the programming round, although traditional LeetCode prep wasn't directly applicable, brushing up on concurrency mechanisms in my preferred language would have been beneficial.