Dmitri Volkov
Technical Editor, System Design
Dmitri breaks down system design and backend interview questions into reusable frameworks, with a focus on trade-offs, scaling, and the follow-up questions interviewers actually ask.
- System design
- Distributed systems
- Backend engineering
Articles by Dmitri Volkov
Payment System Design Interview: Idempotency and Ledgers 2026
A payment system design answer lives or dies on correctness. This guide covers idempotency keys, double-entry ledgers, and reconciliation, then walks through exactly what happens when a charge times out.
Backend Engineer Interview Questions and Prep Guide (2026)
Backend loops test far more than LeetCode. This guide maps what each round checks at each level and walks through the API design round most prep guides skip.
Notification System Design Interview: Push, Email, SMS 2026
A notification system design answer that scores well is channel-agnostic, queue-backed and idempotent. Here is the full architecture, the trade-offs, and the reliability checklist interviewers grade against.
News Feed System Design: The Complete Interview Answer (2026)
A complete news feed system design answer for 2026 interviews, with real capacity math, a worked celebrity-problem example, a hybrid fan-out design, and the ranking basics interviewers now expect.
Design a Rate Limiter: System Design Interview Guide (2026)
A rate limiter is one of the most common system design interview questions, and one of the easiest to answer shallowly. This guide gives you the algorithm decision table, working code, and a distributed Redis design that holds up to senior-level follow-ups.