ETag in APIs — From First Principles to Code

Ever wondered what that mysterious “ETag” header in APIs really does? 🤔

In this video, we break down ETags from the ground up — what they are, why they exist, and how they make your APIs faster and safer! You’ll see how cache validation, optimistic concurrency, and retries all rely on this tiny but powerful header. We’ll wrap it up with a full Python Flask demo showing how to implement and test ETags in real-world REST APIs.