Yelp Engineering and Product

Nurdan Almazbekov, Infrastructure Security

September 26, 2025

Introduction Yelp heavily relies on Amazon S3 (Simple Storage Service) to store a wide variety of data, from images, logs, database backups, and more. Since data is stored on the cloud, we need to carefully manage how this data is accessed, secured, and eventually deleted—both to control costs and uphold high standards of security and compliance. One of the core challenges in managing S3 buckets is gaining visibility into who is accessing your data (known as S3 objects), how frequently, and for what purpose. Without robust logging, it’s difficult to troubleshoot access issues, respond to security incidents, and ensure we...

Jonathan Baird, Software Engineer; Xin Shen, Software Engineer

July 8, 2025

A little while ago, we published a blog post on CHAOS: Yelp’s Unified Framework for Server-Driven UI. We strongly recommend reading that post first to gain a solid understanding of SDUI and the goals of CHAOS. This post builds on those concepts to delve into the inner workings of the CHAOS backend and how it generates server-driven content. To briefly recap, CHAOS is a server-driven UI framework used at Yelp. When a client wants to display CHAOS-powered content, it sends a GraphQL query to the CHAOS API. The API processes the query, requests the CHAOS backend to construct the configuration,...