If you use Prebid for video or other complex ad formats, there’s an important infrastructure change ahead. Microsoft (via Xandr) has announced it will retire its publicly hosted Prebid cache on April 30, 2026.
This change affects a large portion of the publishing ecosystem. While there is still time to act, it’s worth understanding how you’re impacted now so you can evaluate your options without urgency or disruption.
What is a Prebid cache (and why does it matter)?
In header bidding, some creatives — especially video and AMP ads — are too large to be passed directly during an auction response. A Prebid cache temporarily stores those creatives and returns a reference so they can be retrieved and rendered correctly when an ad wins.
If a cache endpoint is unavailable:
- Certain video ads may fail to render
- Revenue-critical formats can be disrupted
What's changing on April 30, 2026?
Microsoft/Xandr is shutting down its public Prebid cache service, which has historically been used by many publishers. After April 30, 2026, any Prebid configuration still pointing to that endpoint will need an alternative cache in place.
What's the risk if no action is taken?
- Video and other complex creatives may stop rendering
- Publishers could experience lost impressions and revenue
- Engineering teams may face unnecessary last-minute work
How JWX is addressing this
JWX is providing a managed, production-grade Prebid cache so publishers can transition safely and on their own timeline.
Publishers have three supported paths:
- Option A: Already using the JWX ad server
You’re fully covered. No action is required.
- Option B: Use the JWX cache only
Keep your existing ad server and Prebid setup and simply update the cache endpoint. This is a fully supported, long-term option designed to minimize engineering work.
- Option C: Migrate to the JWX ad server
For publishers who want to reduce operational complexity and consolidate infrastructure, migration is available — but optional.
Our priority is uninterrupted ad delivery — regardless of whether a publisher migrates to the JWX ad server.
Why some publishers choose to migrate to the JWX ad server
Migration is not required to solve the cache change, but some publishers choose it for broader operational reasons:
- Reduced infrastructure and maintenance burden
JWX operates and maintains the Prebid, cache, and serving infrastructure, removing the need for publishers to host, monitor, and upgrade these components themselves.
- Simplified Prebid and demand-partner management
Demand integrations and Prebid configuration are managed centrally, reducing custom code, engineering involvement, and ongoing maintenance.
- Access to JWX-enabled demand
The JWX ad server & built-in exchange allow publishers to tap into premium demand with an in-house sales team, agency partnerships, and direct DSP integrations.
- Streamlined server-side infrastructure
Publishers see reduced page-level overhead by leveraging server-side SSP integrations while managing both server-side and client-side demand in one unified platform.
What action is required now?
There is no immediate action required, but this is a change worth getting in front of early. Reaching out now allows you to clearly understand how your current setup is affected and calmly evaluate your options — without pressure or last-minute decisions.
Your JWX account team can:
- Confirm whether your current Prebid setup is impacted
- Review the lowest-effort path forward
- Help you plan well ahead of the April 30, 2026 deadline