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IAB Compliant Web Player Guidelines
IAB Compliant Web Player Guidelines
Luke avatar
Written by Luke
Updated over a week ago

If you use the web players from Simplecast, you are all set. However, if you choose to use a custom audio player on your third party site, you must adhere to the following guidelines to be IAB compliant.


HTML5 allows you to add an attribute, ‘preload’,  which controls when media is loaded on the page. If this is set to true all visitors to your site (and pages with audio players supporting preload) will  force your download counts to be artificially inflated. To ensure accurate listen counts, IAB guidelines mandate that this attribute is not set. This ensures that your media is not automatically downloaded, and only downloaded when initiated by the visitor.


HTML5 allows you to add an attribute, ‘autoplay’, which, when set to true, begins playing the audio immediately when the containing page is loaded. This hinders the user’s experience and inflates listen counts. To ensure accurate listen counts, IAB guidelines mandate that this attribute is not set. This ensures that your media is not automatically downloaded, and only done so when initiated by the visitor

Why are Autoplay and Preloading bad ideas?

  • Your listeners may experience a slow page load when either of these attributes are set to true, as the audio for your show will compete for download bandwidth and speed with the other elements of your page. This can cause performance issues, especially on mobile browsers.

  • Your analytics will not accurately reflect how many people truly listened and enjoyed your show. Autoplay and preload will count as a ‘listen’ an instance in which someone simply happened across your site, but never intended to download the show or pay attention to it. It would be inaccurate to include those visits in your statistics. This would not contribute to your understanding of your audience and what you need to grow and succeed as a podcaster.

  • Your listeners may not enjoy the autoplay experience. If they are in an environment in which it would be uncomfortable to have audio start playing from their device, it may deter them from using and returning to your site.

  • In the example in the previous bullet, this issue is exacerbated when the user is visually impaired, as it may take them longer to figure out how to stop the audio from playing.

File requests

For a full download, ask for the entire file in one go. For a progressive download, ask for the file in slices (byte range). This way a full download can be distinguished from a progressive download.

Enclosure URLs

Do not modify the enclosure URL when requesting media, don’t add extra parameters.


Do not cache podcast episodes on your servers. Always download the latest episode from the enclosure URL for every app user wanting to listen.


Use the GUID, as opposed to episode URL, title, publication date, etc., to identify new episodes in the RSS feed that should be automatically downloaded to a user’s device. The GUID is designed to be persistent through changes to hosting environment, titles, etc.

Automatic Downloads

  • Employ an “automatic download unsubscribe” behavior (e.g. - stop auto downloads after 5 episodes of non-listens).

  • Do not automatically download all episodes (e.g. back catalog episodes) by default. This creates unnecessary drain on the publishers’ servers and consumes users’ bandwidth.

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