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Sierra is an AI company that builds conversational AI agents to help businesses improve customer experience through automated, personalized support. Founded by Bret Taylor and Clay Bavor, it is known for its enterprise-focused AI platform that enables companies to deploy branded AI agents.

7 interview notes · updated Jul 2026

sierra·Software Engineer·Technical Phone Screen

Jun 2026
Interviewed for a software engineering role at Sierra and got a data structure design problem that looked deceptively straightforward at first glance. One round, coding focused.
  • Design an OrderedStream class that accepts n items tagged with unique 1-based IDs and values. The insert method should store the value at the given ID position and return the longest contiguous sequence of already-inserted values starting from the current pointer, advancing the pointer past whatever gets returned.

“The pointer mechanic is where I tripped up initially.”

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sierra·Software Engineer·Technical Phone Screen

May 2026
Coding interview at Sierra for a software engineer role. One problem, fairly involved, and the kind of thing that sounds manageable until you're actually writing it out.
  • Write a function that splits a Markdown document into ordered chunks where each chunk stays within a given character size limit, and any chunk that starts mid-section must re-include all the active parent headers before the first line of content.

“This one took me a minute to even parse what they were asking.”

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sierra·Software Engineer·Technical Phone Screen

May 2026
Sierra SWE interview with a coding round focused on interval manipulation. Two tasks: merging overlapping intervals with concatenated text, then detecting overlaps and gaps. Pretty algorithmic for what I expected, but not unreasonable.
  • Given a list of time intervals, each with a start time, end time, and text label, write a function that sorts and merges overlapping intervals. The merged interval should span from the earliest start to the latest end, and its text should be the concatenated labels of the merged intervals in chronological order.
  • Using the original unmerged intervals, write functions to detect: (1) whether any two intervals overlap, and (2) whether there is any gap between the global start and global end. What is the time and space complexity of your approach?

“Sorting first was obvious enough, but I fumbled the text concatenation part initially.”

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sierra·Software Engineer·Technical Phone Screen

Apr 2026
Sierra SWE interview with a coding problem around chunking markdown files. Pretty niche problem, not your typical leetcode grind, but the edge cases were where it got interesting.
  • Given a markdown file, split it into chunks that each respect a maximum size limit. When a chunk boundary cuts into content that falls under one or more headers, the new chunk must start by repeating those ancestor headers before the content.

“The base chunking part felt manageable but the header-prepending requirement is where I started second-guessing myself.”

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sierra·Software Engineer·Recruiter / HR Screen

Apr 2026
Interviewed for a software engineering role at Sierra. Just one question worth noting from what seems like an early screen, pretty standard stuff about job search motivation.
  • Why are you looking for a new role right now?

“I always fumble this one a little.”

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sierra·Software Engineer·Technical Phone Screen

Apr 2026
Had a coding round at Sierra for a Software Engineer role. Pretty focused on streams and iterators, with a follow-up that pushed into system design territory faster than I expected.
  • Design a class MultiplesStream(k) where each call to next() returns the next multiple of k in ascending order (k, 2k, 3k, and so on). Then extend it to handle multiple base integers, merging all their multiples in sorted order with no duplicates.

“The basic version was fine, just a counter times k, nothing to it.”

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sierra·Software Engineer·Technical Phone Screen

Apr 2026
Sierra SWE interview had a pretty meaty coding problem around stream merging. One round, focused on algorithm design and complexity analysis. Not a lot of fluff, they wanted to see if you actually knew your data structures.
  • Design a MergeStream class that takes multiple sorted integer streams (each with next() and hasNext()) and returns the globally smallest next value across all streams until they're all exhausted. Walk through the time complexity of each next() call and explain how you'd handle streams that are empty or finite.

“I knew the min-heap approach going in but fumbled a bit explaining why it's O(log k) per call.”

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