This article was originally published on AI Study Room . For the full version with working code examples and related articles, visit the original post. System Design Fundamentals 2026: A Developer Guide to Scalable Applications System Design Fundamentals 2026: A Developer Guide to Scalable Applications System Design Fundamentals 2026: A Developer Guide to Scalable Applications System Design Fundamentals 2026: A Developer Guide to Scalable Applications System Design Fundamentals 2026: A Developer Guide to Scalable Applications System Design Fundamentals 2026: A Developer Guide to Scalable Applications System Design Fundamentals 2026: A Developer Guide to Scalable Applications System Design Fundamentals 2026: A Developer Guide to Scalable Applications System Design Fundamentals 2026: A Developer's Guide to Scalable Applications System design interviews get all the attention, but the real value is in day-to-day decisions: should you extract that service? Add a cache? Reach for a message queue?…