BlackRock Software Engineer interview questions

16 Software Engineers have shared notes from their BlackRock interviews, with the questions they were asked in each round. That is 80% of the 20 BlackRock interview notes on Screna AI.

16 Software Engineer interview notes

BlackRock·Software Engineer·Technical Phone Screen

Jul 2026
Went through a logic-based scheduling puzzle for a Software Engineer role at BlackRock. Not a traditional coding round, more like a constraint-satisfaction problem dressed up as an interview question. Felt a bit thrown off at first but worked through it systematically.
  • Three candidates are each assigned to one of three consecutive days. Given a set of ordering and exclusion constraints, determine which candidate interviews on which day and explain your reasoning.

“I stared at this for a second because it felt more like a logic puzzle than a software question.”

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BlackRock·Software Engineer·Onsite - Behavioral / Leadership

Jun 2026
Behavioral round for a software engineer role, pretty much centered on cultural fit with UBS-style values. One question, two parts, and I definitely underestimated how much structure they wanted.
  • Walk me through two examples from your past work: one where you demonstrated client focus and collaborative problem solving, and another showing risk awareness and integrity. For each, cover the situation, what you did, the trade-offs you weighed, and the result.

“The trade-offs part is what tripped me up.”

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BlackRock·Software Engineer·Technical Phone Screen

Jun 2026
BlackRock quant engineer interview, one question that sounds deceptively open-ended but actually requires you to have thought carefully about where your mental models break down outside their home domain.
  • Give a concrete example of a problem outside of finance where you applied a markets or quantitative thinking lens. What worked and what failed to translate?

“This one tripped me up more than I expected.”

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BlackRock·Software Engineer·Technical Phone Screen

Jun 2026
BlackRock software engineer interview with two coding problems back to back. One graph/tree problem and one number theory thing. Nothing behavioral, just straight into the code.
  • Given a list of employee-manager pairs forming a company hierarchy tree, and two employee names, find the number of edges on the shortest path between them in the tree.
  • Implement a function that checks whether repeatedly applying 'sum of squares of digits' to a number eventually reaches 1. Provide a solution using a seen-values set and a second solution using O(1) space cycle detection.

“My first instinct was to compute depths and find the lowest common ancestor, which works but I fumbled explaining the LCA part clearly under pressure.”

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BlackRock·Software Engineer·Technical Phone Screen

Jun 2026
BlackRock software engineer interview with a binary tree traversal question that asked for both recursive and iterative solutions plus complexity analysis. Pretty standard algorithms round but the dual-implementation requirement added a layer I wasn't fully expecting.
  • Given the root of a binary tree, implement in-order traversal both recursively and iteratively using a stack, then walk through the time and space complexity of each approach.

“The recursive version came out fine, muscle memory at this point.”

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BlackRock·Software Engineer·Technical Phone Screen

Jun 2026
BlackRock Data Engineer interview with a coding problem on interval merging. Pretty standard algorithmic round, nothing too wild, but the problem has enough edge cases to trip you up if you're not careful.
  • You're given a sorted list of non-overlapping intervals and a new interval. Insert the new interval into the list, merging any overlaps, so the result stays sorted and non-overlapping.

“Classic interval problem but I always forget to handle the edge cases cleanly under pressure.”

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BlackRock·Software Engineer·Technical Phone Screen

Jun 2026
BlackRock quant engineer interview, one meaty technical question about model design and validation. Pretty rigorous for a single prompt but it covers a lot of ground if you actually dig into it.
  • Walk through a quantitative model you've built or worked with to analyze market data. What was it trying to do, what assumptions did it depend on, how did you test those assumptions, and where did the model break down?

“This is one of those questions where the answer you give says more about your judgment than your math skills.”

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BlackRock·Software Engineer·Online Assessment (OA)

Jun 2026
Took the BlackRock OA for the Summer 2027 internship and it was a bit of a mess. Two coding problems, one easy and one medium, but the real pain was the explanation portion where the code just didn't show up on screen and I ended up talking at nothing.
  • Solve a LeetCode easy-level coding problem and explain your solution.
  • Solve a LeetCode medium-level coding problem and explain your solution.

“I've done this problem so many times it should've been automatic.”

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BlackRock·Software Engineer·Technical Phone Screen

Jun 2026
Technical screen for a data engineer role at BlackRock, two interval problems back to back. First one was more conceptual, second one they actually wanted working code, which I wasn't fully expecting.
  • Given an unsorted array of integer intervals, merge all overlapping ones and return the result.
  • You have a sorted list of non-overlapping intervals. Insert a new interval and return the merged result with no overlaps.

“They said I didn't need to write full code, just explain the algorithm clearly.”

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BlackRock·Software Engineer·Technical Phone Screen

Jun 2026
BlackRock software engineer interview with two back-to-back coding problems and a tight two-minute verbal explanation window after each one. Pretty focused on fundamentals but the submission constraint made it stressful.
  • Implement a sorting function from scratch (no built-in sort) that returns a list of integers in non-decreasing order. After coding, explain your choice of algorithm along with its time and space complexity and whether it's stable.
  • Write a function that takes two iterables of integers and returns a sorted list of unique elements appearing in both. You need to handle input parsing yourself, cover edge cases like empty inputs and duplicates, and explain time and space complexity. Only one submission allowed.

“I went with merge sort because I could at least explain stability confidently.”

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