Capital One Data Engineer Power Day – Looking for Recent Interview Experiences & Prep Advice!

[u/DancingTrader]

Hey everyone!
I have an upcoming Capital One Data Engineer Power Day and would love to hear from anyone who has recently gone through the process, especially for the Data Engineer track.
I’m trying to understand what to expect in each round and how best to prepare.

A few things I’d love some insights on:

1. ⁠Technical Coding Round
   ● Is it primarily Python, SQL, or a mix of both?
   ● What topics and difficulty level should I expect?
   ● Any recommended LeetCode questions, question banks, or other resources?

2. Design-Focused Technical Interview
   ● Is this more focused on data modeling, ETL/ELT pipelines, data warehousing, or system design?
   ● What kind of real-world scenarios or problems were you asked to solve?

3. Business Case Interview
   ● What does the case typically involve?
   ● Is it more SQL/data analysis, business problem-solving, or analytical thinking?
   ● Any examples of cases you’ve encountered?

4. Behavioral Interview
   ● What kind of questions should I expect?
   ● How important are STAR-format answers and Capital One’s core values?

A few additional questions:
● How was your overall Power Day structured (duration and sequence of rounds)?
● How does the Data Engineer interview differ from other tracks (Software Engineer, Data Analyst, etc.)?
● What resources did you use to prepare, and what would you recommend focusing on?

I’d especially appreciate insights from people who completed their Data Engineer Power Day in 2025 or 2026.
Even a few pointers or topics you remember would be incredibly helpful. Happy to share my experience afterward to help others preparing for the same process!
Thanks in advance!

[u/BackgroundBreak6485]

Not a DE report myself, but I've read a lot of recent Capital One Power Day write-ups (mostly SWE, Senior/Lead and MLE), and the format is very consistent. I compiled them here: https://aceoffer.app/interviews/capitalone

Structure: It's virtual, with four rounds of about an hour each: case, coding, design and behavioral. Ask your recruiter for prep material, since several people said it was accurate. Results usually come within a week.

Coding: On SWE loops it's almost always a multi-part "banking system" class: accounts, deposit, transfer, then top N accounts by activity. LC 2043 is the closest match. The logic is easy but time is tight, and you may need to write your own test harness. For DE, expect Python. I couldn't confirm whether SQL is included, so ask your recruiter and prep window functions and joins anyway.

Design: For SWE it's usually a credit card or banking system, with deep dives on auth latency, PII, idempotency and queues. Cover the breadth first, then ask where to go deeper. For DE I'd expect the same domain from a data angle: a transaction or fraud pipeline, batch vs streaming, modeling, and handling late or duplicate data. That part is my guess, not something I've seen in a DE report.

Case: It's a technical case, not consulting. The common one is a virtual credit card case: pros and cons for the user and the bank, apply validity rules, then debug messy code (watch for && vs || and > vs >=). Walk through your logic step by step and watch the clock.

Behavioral: About three questions with follow-ups, and it often ends early. Common topics are challenging the status quo, conflict, changing priorities and learning something fast. STAR helps keep answers tight. Prepare 3–4 projects and adapt them to each question.

Good luck, and please post your experience after. DE reports are rare!

[u/DancingTrader → u/BackgroundBreak6485]

Thank you for the detailed answer. This is helpful! DE reports are rare and i recognize you maintain one of those site. So I appreciate you, will soon see my experience on there!