With the scheduled deprecation date for Microsoft’s public Prebid cache service approaching, it’s high time that publishers prepare for the shutdown.

In 2025, Microsoft announced it would deprecate the provision of its Prebid cache service on April 30, 2026. Although little time is left till the deadline, up until recently many publishers were hoping that the company would reverse its decision. Unfortunately, this didn’t happen. 

Now that less than a week is left until the scheduled deprecation date, it’s time for publishers to review their existing tech implementations and migrate to another caching solution, if needed, promptly.

Why It Matters

If you’re a publisher monetizing your inventory with video ads, specifically selling it via programmatic campaigns (i.e. via video header bidding), you’ve likely relied on Microsoft-hosted Prebid cache service to store and retrieve creatives, thereby ensuring all video ads are being delivered on your digital properties smoothly, without any disruptions. 

And now that this service will soon no longer be available, the key task is to check if your video ad activities are in some way affected by this change, then migrate them to one of the other solutions, currently offered on the market, if needed. 

How to Know if You’re Affected

According to Prebid’s recommendations, the fastest way to confirm if a publisher is affected by the upcoming deprecation of Prebid cache service is to enter: pbjs.getConfig().cache in console and see if the returned result includes a URL pointing to the adnxs.com domain.

If it does, act on it soon. 

Existing Alternatives to Microsoft’s Prebid Cache Service

In short, digital publishers currently have several options to select from in terms of alternative caching solutions. These include both the server-side and client-side options. 

Although Microsoft mentions local caching as the preferred option for ensuring bandwidth use reduction for all parties involved, all solutions, in fact, have their certain specifics, which should be taken into consideration.

  • Server-side caching

When it comes to server-side caching, publishers can either implement self-hosted Prebid cache, available via Prebid Server, or select one of the paid caching options, provided by large video ad platforms, like Magnite, Mediavine or PubMatic, just to name a few, especially if they’re working with SSPs or other managed platforms. 

In this respect, the former option implies more control over the entire process, yet may lead to significant operational overhead. Meanwhile, the use of the latter allows streamlining the technical aspects of the setup, yet it might cost much more in the long run.

It’s also possible to work with one of the so-called independent providers, which offer Prebid caching services, like Bidcliq, for instance, that require little change on the publisher’s side upon the deprecation of Microsoft’s Prebid caching support. However, this will also result in additional cost for publishers, depending on their video ad serving volumes. 

  • Client-side local caching

Since version 10.23, Prebid has enabled local client-side caching to work around Google Ad Manager’s requirements to cache a VAST URL.

While the implementation may require certain changes on the publisher’s side, this solution should require less financial investment at least in the short term. 

Tip! Learn more on how to implement client-side local caching in Prebid’s implementation guide.

Final Thoughts

All things considered, whatever the solution, it’s crucial to evaluate its existing limitations and technical migration requirements before implementation. Therefore, it’s recommended to consult your SSP and other technical partners in advance.