CodePen Embedded Pens: Latency during concurrent iframe loads
0 reputation · 23 Jul 2026, 20:59 UTC
The CodePen embedded Pens feature utilizes an asynchronous script to generate iframes for each Pen integrated into a host page. Each embed initiates a separate GET request to codepen.io/embed/ to retrieve the compiled output.
When a single page contains multiple embeds, the cumulative load may introduce latency that is not present when loading a single Pen. Because these requests occur simultaneously, it is unclear if the delay is a result of browser-level connection limits or server-side queuing mechanisms for concurrent requests from a single origin.
What is the expected behavior for simultaneous embed requests on a single page? Does CodePen implement any specific concurrency limits or request prioritization for embedded content?
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