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Mercor Interview Experiences
3935 interview stories from candidates at 857 companies: how each round went, what was asked and how it ended. Every company page links to practice questions in the same style.
- 3935
- Experiences
- 857
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- 532
- Offers
22 results
- No-Coding Technical Screen with Code-Reading Questions, Did Not PassMercor · Software Engineer · Technical Screen · Oct 2026Rejected
I applied online. There is no recruiter screen - first call is a HM screen where they ask you basic questions. Next screen is a 30 minute technical screen with no coding. Mine had 4 questions - Tell me the worst sorting algorithm - (n!) and explain how you would calculate each permutation You visit two coffeeshops A and B and order 2 drinks from each. Each drink gets a quality score. What is the…
- Technical Screen with Bloom Filter and Payment Idempotency DebuggingMercor · Software Engineer · Technical Screen · Oct 2026
Almost all of these were questions I had already seen in interview experience posts! Worst sorting algorithm: I talked about enumerating every permutation and checking whether each one is sorted. Coffee shop: A and B each buy two cups of coffee. What is the probability that A's two cups taste better than B's two cups? There are 1M user_ids. How do you efficiently check whether an id exists, and a…
- 30-Minute Rapid-Fire Technical Screen, Rejected After Three QuestionsMercor · Software Engineer · Technical Screen · Sep 2026Rejected
The first round at Mercor was a 30-minute live technical interview. It was rapid-fire Q&A, where you try to answer as many questions as possible. I only got through 3 questions, so I didn't pass. The first question was to explain in detail a sorting algorithm faster than O(n^2). I gave merge sort. The second question was to give one slower than O(n^2). For brute force you can shuffle and then com…
- A Rushed 30-Minute Screen on Sorting, Probability, and a Cache Race ConditionMercor · Software Engineer · Technical Screen · Sep 2026
The interviewer was a principal from Caltech. He talked fast and used a lot of technical jargon, like a college professor would. It was rushed, only 30 minutes. Explain a sorting algorithm better than O(N^2). Merge sort — recursively split the array into left and right halves until there are only 2 elements left, then merge by inserting the smaller of the two into a new array and returning it (N…
- Applied AI Tech Screen with an Async Refund Debugging Question and Rapid-Fire LLM QuestionsMercor · Software Engineer · Technical Screen · Sep 2026
Today I had a tech screen for Mercor's Applied AI role. The debugging question: The other rapid-fire questions: What is idempotency, and why do we need idempotent operations? What is RAG, and how is it related to fine-tuning? How would you handle context limit exceeded in an LLM application? LLM calls are usually stateless. How would you make an LLM application stateful? How would you handle prom…
- Three Onsite Rounds, Kicked Out of the Meeting Room Mid-InterviewMercor · Machine Learning Engineer · Onsite · Sep 2026
I finished interviewing at this company yesterday. My background is physics AI. I did competitive programming back in high school, and I figured I could cram a system design book for a few days and pass this onsite. Turns out I was still too green. The questions were pretty standard; it's on me for being too weak and wasting the opportunity. The interview was chaotic: in the middle of it, people…
- 25-Minute Screen, Sorting Complexity and Cache Review, RejectedMercor · Software Engineer · Technical Screen · Aug 2026Rejected
Sorting Complexity They asked me to come up with a sorting algorithm that is as inefficient as possible and explain its time complexity. One idea is to enumerate all permutations of n distinct elements and check one by one whether each is sorted. There are n! permutations in total and each check takes O(n), so the worst-case time complexity can reach O(n × n!). Strictly speaking there is no singl…
- Mercor Software Engineer interview canceled before three algorithm prompts could be answeredMercor · Software Engineer · Jul 2026
The process was chaotic from the start. My first interview was canceled, and when I finally got a second one, it ended extremely quickly, in around five minutes. Before it started, I was given a Google document with three data-structures and algorithms prompts, including BFS and two pointers. I tried to take a couple of minutes to get oriented, but the interviewer canceled before I could write an…
- Mercor Software Engineer interview with a three-section HackerRank assessmentMercor · Software Engineer · Online Assessment · Jul 2026
After I applied, the first step was an online HackerRank-style assessment with three sections. It covered data and algorithms, data pipelines, and SQL-style questions, so I had to move between very different problem types one after another. A short time later, I had a 30-minute conversation with the hiring manager. That discussion felt mostly behavioral, with some technical back-and-forth mixed i…
- Mercor Software Engineer interview with resume-tailored AI questionsMercor · Software Engineer · Other · Jul 2026Offer
I went through an interview flow that was entirely AI-based, and I found it surprisingly efficient. The AI generated questions tailored to my resume and the job description, and the experience felt almost human, more like a real conversation than a cold checklist. The questions covered system design prompts and coding and code-practice topics, and I usually had enough time to think through my ans…
- Mercor Software Engineer interview: a three-part HackerRank-style OAMercor · Software Engineer · Online Assessment · Jul 2026
After applying online, I received an online assessment on HackerRank-style tests with three sections. It covered data structures and algorithms, data pipelines, and SQL questions. Not long afterward, I had a 30-minute conversation with the hiring manager. It was mostly behavioral, with a few technical discussions mixed in. It felt like a standard early loop, with the OA setting the tone and the r…
- Mercor Software Engineer interview: AI-generated resume-tailored questionsMercor · Software Engineer · Jul 2026Offer
My interview was conducted entirely through an AI platform. It generated questions tailored to my resume, and I found the process efficient and positive. Even though it used AI, it did not feel like a cold or mechanical interaction. The questions sounded natural, and the exchange felt more human than I expected. It was comprehensive for the time it took but still moved smoothly. I felt the AI pac…
- Mercor Software Engineer interview: five-minute interview with BFS and two-pointer questionsMercor · Software Engineer · Jul 2026
Scheduling went badly from the start. The first interview was canceled after I had already been set up for it, and the second lasted only about five minutes. During that short session, I received a Google Doc with three data structure and algorithm questions, including BFS and a two pointer approach. I needed a couple of minutes to get oriented, but the interviewer canceled before I could write a…
- Mercor Software Engineer interview with concurrency and RedisMercor · Software Engineer · Jun 2026
My interview was brief, around 30 minutes. The interviewer gave me some code and asked me to make it more robust. He nudged me toward concurrency and distributed-systems thinking, including how to process CSV data and coordinate synchronization with Redis. I felt behind because I was still early in graduate school and didn't have deep experience with that specific concurrency and distributed-syst…
- Mercor Software Engineer interview: fast sorting questions and code reviewMercor · Software Engineer · Technical Screen · Jun 2026
One interview felt unusually fast and almost dismissive. I spoke with an engineer who asked quick, random questions, including the slowest sorting algorithm and its time complexity. I then did a quick code review of two functions. The whole decision seemed to happen within about five minutes, and the engineer appeared eager to wrap up after roughly ten. Another round was also very straightforward…
- A Product-Focused Recruiter Screen, Then Sorting Theory and a Concurrency Code ReviewMercor · Software Engineer · Technical Screen · May 2026
Round 1 — Background / recruiting round Self-introduction, plus walk through a project you've worked on recently. They dug deep into the project, but the follow-ups were all from a product angle rather than implementation details: was this decision made by your system or upstream? How do you define "it worked"? What's the success metric for this project? What's your understanding of what Mercor d…
- Half-Hour Online Round of Code Review and Design QuestionsMercor · Software Engineer · Technical Screen · May 2026In progress
Writing up an earlier Mercor fullstack round. It was online, about half an hour, and after I passed I got an onsite. It was mostly reading code to find problems and talking about design. I'm putting this together from my notes, so the order may not match what actually happened. Payment API Code that first calls an external provider to charge the customer, then writes a record to our own database.…
- Mercor Software Engineer interview with a five-hour virtual super dayMercor · Software Engineer · Other · May 2026Rejected
My process started with a recruiter call, followed by an AI-driven stage where I answered LeetCode-style questions and additional technical prompts. After that, I went through a longer "super day" style setup. Mine was virtual and lasted about five hours in total, combining system design, coding, and what they called vibe coding on the same day. It was on the harder side, although I also felt lik…
- Mercor Software Engineer interview: 30-minute data structures and algorithms screenMercor · Software Engineer · May 2026
My first step was a phone screen with the team. It was a tightly structured, 30-minute Q&A focused mainly on data structures, algorithms, and code optimization. What stood out was how closely it stayed to fundamentals and reasoning. I left feeling that it tested whether I could think through tradeoffs clearly and tighten up implementations under time pressure. Given the short format, it still fel…
- Mercor Software Engineer interview through an adaptive AI platformMercor · Software Engineer · Other · Mar 2026
My interview took place entirely through an AI platform. It asked questions based on what I submitted and how that information aligned with the job description. Instead of typing answers, I recorded live audio and video responses while the AI monitored me. The most important thing for me was keeping my answers consistent with what I had already told it about my background. The AI kept tying its q…
- Mercor Software Engineer interview with a rushed interview and a no-showMercor · Software Engineer · Online Assessment · Mar 2026
My application moved quickly at first and then ended without much closure. After speaking with a recruiter and taking an online assessment, I submitted my solution and received a denial about two weeks later. The experience was okay overall, but I never got any feedback, so I couldn't tell what went wrong. Later, I had a separate and more upsetting experience. I was rejected after a very brief in…
- Mercor Software Engineer interview with an Apple Silicon compatibility checkMercor · Software Engineer · Mar 2026
The interview was conducted by an AI agent, and I could complete it by phone or computer. The process itself was fairly straightforward, with the AI asking questions based on my submissions. The problem came with the compatibility check in the middle of the process. They specifically checked whether I was using Apple Silicon Macs. That felt like a major miss to me because the tools I needed weren…
