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Confluent·Software Engineer·Onsite - System Design / Architecture·Senior

Senior
Jun 2026

Summary

System design round at Confluent for a software engineer role. Just the one question, no whiteboard or diagram required, but they wanted real specifics on the data model and API layer.

Questions Asked (1)

Q1

Design an RSS news feed system. Walk through your database table design and API design in detail.

System DesignData ModelingAPI & Integrations
Author's notes

No diagram needed, which I thought would make it easier.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements (scale, read/write ratio, feed types) and then present a high-level architecture. Dive into database schema design with normalization considerations and API endpoints that support efficient feed retrieval and updates. Emphasize trade-offs and scalability, especially given Confluent's focus on event streaming.

Pro tip: Leverage Confluent's core competency by discussing how Kafka can be used to ingest and process feed updates in real-time, and how that integrates with your database and API layers.

1. Clarify Requirements and Scope

Ask about expected scale (users, feeds, items), read/write patterns, latency requirements, and whether feeds are personalized or global. This ensures your design meets actual needs.

2. High-Level Architecture

Outline components: feed ingestion, storage, API layer, and caching. Mention how data flows from sources to consumers, possibly using a message queue like Kafka.

3. Database Schema Design

Propose tables for feeds, items, subscriptions, and user-feed mappings. Discuss indexing, partitioning, and denormalization for read efficiency.

4. API Design

Define RESTful endpoints for creating feeds, adding items, subscribing, and fetching feeds. Include pagination, filtering, and authentication considerations.

5. Scalability and Trade-offs

Discuss how to scale reads/writes (caching, sharding, replication) and trade-offs between consistency and availability. Mention monitoring and failure handling.

Key Points to Mention

  • Use of Kafka for real-time feed ingestion and processing
  • Database choice (SQL vs NoSQL) based on access patterns and scale
  • Indexing strategies for efficient feed retrieval (e.g., composite indexes on user_id and timestamp)
  • API pagination using cursor-based or offset-based methods
  • Caching layer (e.g., Redis) to reduce database load for hot feeds
  • Handling feed updates and fan-out on write vs fan-out on read

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.