Design a Credit Card System: Login, Authorization with Fraud Checks, Bureau Reports

Also reported as Credit Card Platform System Design

System DesignCapital OneLast reported October 2026Medium Frequency

Problem Overview

A system design question, reconstructed from 9 candidate reports. Sign in to read the write-up.

5 candidate-reported follow-ups — the probes candidates report being asked, with the trigger for each
The problem statement — full requirements, constraints, and edge cases
Approach and trade-offs — what passing candidates did, and the mistakes that sink people

Unlock the full Capital One catalog

Full problem statements, candidate-reported follow-ups, and walkthroughs — for every Capital One question.

Already a member? Sign in

Verified Source

Every question is reconstructed from multiple independent candidate reports. Follow-ups candidates reported, not invented ones.

Codex Fact-Checked

Technical claims, formulas, and scale numbers are reviewed against primary sources.

Interviewer Follow-ups

The follow-ups candidates reported, with the trigger that prompts each one — plus the mistakes that sink people.