Monday is a blog or publication focused on productivity, time management, and personal development. Readers can find articles on topics such as goal setting, task prioritization, and habit formation. Additionally, they can learn about productivity tools, techniques for optimizing workflow, and strategies for achieving work-life balance.

monday Engineering

A load test on monday.com's AI Reports feature revealed a critical race condition caused by a hidden singleton pattern. When multiple users simultaneously generated reports, a WorkdocsAPIService registered as a singleton shared mutable state across concurrent requests, causing workdoc IDs to override each other and trigger 400 errors. The bug remained undetected in production due to low adoption rates and high pod count, which minimized collision probability. The investigation traced through multiple hypotheses before discovering the singleton registration issue, highlighting the importance of load testing, end-to-end concurrent testing, and preferring stateless class designs in asynchronous environments.

Unmasking a hidden singleton

Rabbit holes, dead ends, and the “aha!”