ETags And Conditional HTTP Requests

An animated walkthrough of HTTP caching using ETags, showing a client and server exchanging messages step by step. The first GET request returns a response body tagged with an ETag value. A later request sends that ETag back via If-None-Match, and the server replies with 304 Not Modified instead of resending data. The animation visualizes how conditional requests save bandwidth, useful for students or developers learning web performance and caching fundamentals.

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The prompt that made it

Explain ETags in HTTP caching in a clean mathematical explainer style. Show a client on the left and server on the right. Animate the GET request, response body, ETag "abc123", then another request containing If-None-Match, followed by the server returning 304 Not Modified. Use minimal text and smooth transitions.

Make your own version

Make the next one in this series

• Show how Cache-Control max-age interacts with ETag validation over time
• Animate the difference between strong and weak ETags during validation
• Compare Last-Modified headers versus ETags for cache freshness checks