Microsoft announced on December 12, 2025, that it’ll deprecate the widely-used public Prebid Cache service on April 30, 2026, creating substantial disruption for hundreds of publishers who rely upon the infrastructure to ship video commercials by means of header bidding. Based on Microsoft Be taught documentation, implementations utilizing the cache endpoint http://prebid.adnxs.com/pbc to retailer and retrieve video creatives should migrate to a different resolution earlier than the deadline.

The deprecation follows Microsoft’s August 2025 notification that originally set the shutdown for January 31, 2026. Pat Diggins, Senior Product Supervisor at Microsoft, introduced in a LinkedIn post two weeks in the past that the corporate prolonged the timeline by three months to April 30, offering publishers further time to implement alternate options. “Prebid.js now presents a superior resolution, native caching for video bids, which offers a greater consumer expertise and diminished community latency,” Diggins acknowledged within the December announcement.

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Data shared by Ian Meyers, Co-Founder at Sincera (acquired by The Commerce Desk), reveals the dimensions of the disruption. Evaluation posted to LinkedIn exhibits the Microsoft-hosted cache presently represents greater than 60 p.c of all configured Prebid Cache endpoints. The pie chart visualization demonstrates Microsoft’s dominant place, with https://prebid.adnxs.com/pbc/v1/cache commanding the bulk share in comparison with competing companies from Rubicon Mission, MediaVine, JourneyManX, Pubmatic, and different suppliers.

Patrick McCann, Senior Vice President of Analysis at Raptive, warned publishers in a LinkedIn post on December 9 that the deprecation creates a number of migration challenges. “For those who’re a writer utilizing Prebid for video adverts, you most likely depend on the free Prebid Cache run by Microsoft,” McCann wrote. The shutdown forces publishers to decide on amongst restricted choices: arise their very own cache infrastructure, discover vendor options and reconfigure Google Advert Supervisor creatives, stop utilizing Prebid for video fully, or implement native caching.

The timing creates explicit urgency as a result of various vendor options stay scarce. Based on McCann’s evaluation, “I do know of none up to now” when describing distributors providing turnkey Prebid Cache internet hosting as of early December. This hole available in the market has prompted a number of corporations to announce substitute companies.

Shinka, an impartial advert tech infrastructure supplier for related tv and digital out-of-home publishers, introduced an enterprise-grade Prebid Cache resolution on December 16, 2025. Based on an ExchangeWire announcement, Shinka’s cache launches on infrastructure presently processing billions of advert requests month-to-month for enterprise purchasers and lately achieved SOC 2 Sort 1 compliance. Kieran Greene, CEO of Shinka, acknowledged: “When Microsoft introduced the deprecation of their Prebid Cache service, we instantly recognised the crucial infrastructure hole this creates for video publishers. We have spent years constructing mediation and header bidding infrastructure.”

Aditude concurrently launched a competing free Prebid Cache resolution focusing on enterprise publishers affected by Microsoft’s shutdown. Based on supplies on the company’s landing page, the service processes billions of video advert requests month-to-month and presents zero-cost entry to publishers presently utilizing Microsoft’s cache or planning migration. The answer requires publishers to fulfill particular standards together with important month-to-month advert request quantity and technical assets for implementation.

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Microsoft’s really useful migration path facilities on client-side native caching, a function Prebid.js launched to cut back community site visitors whereas working with advert servers. Based on Prebid.org documentation, when native caching is enabled by means of the cache.useLocal configuration, VAST XML is saved as a blob within the browser’s reminiscence moderately than being despatched to a distant cache endpoint. The configuration maintains compatibility with present Google Advert Supervisor VAST creatives, although with one crucial distinction in how artistic URLs are dealt with.

The native caching strategy addresses one longstanding limitation: it eliminates dependency on exterior cache infrastructure. When cache.useLocal is about to true, the distant cache URL endpoint is rarely referred to as. Nonetheless, present GAM creatives configured with VAST advert tag URLs like https://my-pbs.instance.com/cache?uuid=%%PATTERN:hb_uuid%% proceed functioning as a result of hb_uuid will get set to the domestically assigned blob UUID. If the bid wins the GAM public sale and its videoCacheKey is included in a GAM wrapper VAST XML, Prebid updates the VAST advert tag URL with the domestically cached blob URL after receiving the response from Google Advert Supervisor.

Technical issues emerge with the native caching resolution, significantly concerning Google AdX compatibility. A GitHub issue #14014 in the Prebid.js repository paperwork ongoing challenges with implementing native caching alongside Google’s Interactive Media Advertisements software program improvement equipment. McCann referenced this concern immediately in his LinkedIn announcement: “implement native caching (and till we resolve https://lnkd.in/ew8UhB4f, not use AdX anymore).”

The GitHub dialogue reveals the technical complexity publishers face. ReinoutStevens, a contributor, defined that earlier than implementing native caching, Prebid creates the Google Advert Supervisor URL by means of pbjs.adServers.gam.buildVideoUrl and feeds that URL into IMA, which provides quite a few further parameters. These embody supported SDK variations and consumer identification suppliers like a3p. With cache.useLocal enabled, Prebid as a substitute makes use of pbjs.adServers.gam.getVastXml and feeds VAST XML immediately into IMA, bypassing the community name the place IMA would usually add its parameters.

“As Prebid is now doing the community name to GAM (so it will possibly modify the response and inject the cache blob) the params that IMA provides are lacking,” ReinoutStevens wrote on October 23, 2025. The consequence: Prebid companions confirmed improved efficiency with native caching, however “Google their share tanked: variety of requests are steady, however Google is bidding so much much less (resulting from lacking userIds and so on.).”

Publishers following the GitHub thread found that Google Advert Supervisor helps another parameter referred to as ssj (not documented in the usual parameter record) that permits passing consumer IDs to GAM with out counting on IMA’s a3p parameter. Nonetheless, this workaround requires further implementation work and will not totally replicate all of the parameters IMA usually offers.

Robin-crazygames, who collaborates with ReinoutStevens, added one other complication on November 19: bidders utilizing their very own cache infrastructure skilled extreme efficiency degradation when publishers enabled native caching. “Once we experimented with the native cache, these bidders took successful (fairly extreme in some circumstances),” robin-crazygames reported. The problem seems associated to Prebid storing all bids within the native cache no matter whether or not they have been already cached server-side, probably interfering with bidders like Rubicon, Xandr, and Nativo who preserve their very own caching methods.

Microsoft’s stance on the deprecation facilities on selling native caching adoption throughout the business. Based on the unique announcement documentation, Microsoft characterised native caching as “the popular technique providing a smoother buyer expertise and diminished bandwidth for all contributors.” The corporate dedicated to working by means of area of interest use circumstances with the group as core contributors to Prebid.js.

The Microsoft-hosted Prebid Cache originated from AppNexus, which Microsoft acquired as a part of its Xandr buy from AT&T in June 2022. The general public cache service at prebid.adnxs.com/pbc has operated for years as free infrastructure supporting the broader header bidding ecosystem. Publishers integrated the endpoint into their Prebid configurations with out price, enabling video advert supply throughout numerous web sites.

Microsoft’s determination to sundown the cache coincides with broader strategic shifts within the firm’s promoting know-how operations. On Could 14, 2025, Microsoft announced it would discontinue Microsoft Invest DSP by February 28, 2026. Based on Kya Sainsbury-Carter, Company Vice President at Microsoft Promoting, the corporate decided that conventional demand-side platform fashions proved incompatible with their imaginative and prescient for “conversational, customized, and agentic” promoting futures.

The Prebid Cache infrastructure serves a crucial perform in video promoting supply. When video bidders take part in header bidding auctions, those who cache VAST XML on their very own servers present a videoCacheKey that works along side the VAST URL within the advert server. Nonetheless, bidders that do not preserve server-side caching return your entire VAST XML physique. Prebid.js should copy this XML to a publisher-defined cache location on the community by POSTing to a Prebid Cache endpoint, which returns a key used to retrieve the artistic when the video participant wants it.

Publishers implementing their very own Prebid Server cases can configure cache endpoints inside their infrastructure. Nonetheless, many publishers depend on client-side Prebid.js implementations the place the Microsoft-hosted public cache supplied handy zero-configuration infrastructure. The deprecation eliminates this comfort, forcing publishers to both arise cache infrastructure, buy companies from distributors, or undertake native caching with its related technical issues.

Trade dialogue across the deprecation has generated conflicting assessments of influence severity. McCann’s December 9 submit characterizing it as affecting publishers utilizing Prebid for video drew responses noting that Microsoft introduced the change “again in August.” Scott Kay, Principal Engineering Supervisor at Microsoft, responded to the dialogue by highlighting Prebid.js’s native caching capabilities: “Prebid.js helps unlock a quicker, extra environment friendly web by maintaining caching on-device.”

The technical implementation particulars for publishers pursuing the native caching route are documented in Prebid.org’s setConfig reference. The cache.useLocal parameter allows the function, whereas further parameters management timeout values, batch processing, and VAST monitoring capabilities. Publishers can configure: cache.url to specify the Prebid Cache server endpoint, cache.useLocal as a boolean flag for native VAST XML storage, cache.timeout for community request timeouts, cache.vasttrack for extra occasion monitoring knowledge, and cache.ignoreBidderCacheKey to wrap bidder-supplied cache keys in VAST wrappers.

Some publishers have reported profitable native caching implementations regardless of the challenges. The Prebid documentation notes that when native caching works accurately, it will possibly cut back community site visitors and enhance consumer expertise by eliminating the roundtrip to distant cache infrastructure. The blob URLs generated for locally-cached VAST XML perform equally to conventional cache URLs from the video participant’s perspective.

Publishers involved about sustaining Google AdX demand whereas implementing native caching face significantly tough tradeoffs. The unresolved GitHub concern means publishers should presently select between adopting native caching with potential AdX income loss, or sustaining distant caching by means of various suppliers. Some business contributors have proposed treating AdX as a fallback tag moderately than a aggressive bidder, successfully utilizing Prebid to fill stock when header bidding companions present bids and falling again to AdX once they do not.

The broader header bidding ecosystem has skilled important turbulence all through 2025. Prebid.org modified transaction ID handling in August 2025, implementing bidder-specific identifiers that eradicated cross-exchange visibility for demand-side platforms. The IAB Expertise Laboratory declared the adjustments “materially violate the OpenRTB specification,” creating the first major standards clash between the header bidding wrapper and the business requirements physique.

The Trade Desk responded by launching OpenAds in October 2025, forking Prebid’s codebase to protect authentic transaction ID performance. CEO Jeff Inexperienced described the initiative as obligatory to take care of honest public sale mechanics after Prebid disabled cross-exchange transaction ID performance. The corporate reported that transaction ID protection reached 59 p.c of browser-based adverts on the open web earlier than the Prebid adjustments.

Microsoft’s Prebid Cache deprecation provides one other layer of infrastructure uncertainty to an ecosystem already managing important technical transitions. Publishers who’ve standardized on Prebid for header bidding now face compelled migration timelines for video promoting infrastructure, with restricted vendor alternate options and technical challenges throughout the obtainable options.

The April 30, 2026 deadline leaves publishers roughly 4 months from this announcement to implement alternate options. These pursuing native caching should navigate the GitHub issue #14014 issues or settle for potential AdX income influence. Publishers standing up their very own cache infrastructure face improvement timelines and ongoing operational prices. Distributors providing hosted options could emerge, although as of mid-December such choices remained scarce.

Publishers involved in regards to the deprecation can entry Microsoft assist by means of their account managers or by filling out assist types, based on the corporate’s documentation. The Microsoft Be taught announcement emphasizes that native caching represents the popular path ahead, with the corporate positioning the additional three months as enough time for correct testing and validation.

For publishers processing important video promoting quantity by means of Prebid, the infrastructure change represents a crucial operational deadline that requires rapid planning and useful resource allocation. The focus of utilization on Microsoft’s cache endpoint—with knowledge exhibiting greater than 60 p.c market share—means a considerable portion of the programmatic video promoting ecosystem should execute simultaneous migrations throughout the similar compressed timeframe.

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Abstract

Who: Microsoft (previously AppNexus/Xandr) is deprecating its public Prebid Cache service, affecting hundreds of publishers utilizing Prebid.js for video header bidding. Various options have been introduced by Shinka and Aditude, whereas Prebid.org promotes native caching as the popular migration path.

What: The Microsoft-hosted Prebid Cache endpoint at http://prebid.adnxs.com/pbc might be utterly decommissioned, eliminating free infrastructure that shops and retrieves video creatives for header bidding auctions. The cache presently handles greater than 60 p.c of all configured Prebid Cache endpoints. Publishers should migrate to alternate options together with native client-side caching, vendor-hosted options, or self-hosted infrastructure.

When: Microsoft introduced the deprecation on December 12, 2025, with a closing shutdown date of April 30, 2026. The timeline was prolonged from the unique January 31, 2026 deadline introduced in August 2025, offering three further months for writer migration.

The place: The deprecation impacts the worldwide programmatic video promoting ecosystem, significantly publishers implementing Prebid.js or Prebid Server for header bidding on web sites and functions. The influence extends throughout all geographic areas the place publishers use the Microsoft-hosted cache endpoint for video advert supply.

Why: Microsoft characterizes native caching as technically superior, providing higher consumer expertise and diminished community latency in comparison with distant cache infrastructure. The choice coincides with Microsoft’s broader strategic shift away from conventional promoting know-how operations, together with the discontinuation of Microsoft Make investments DSP introduced in Could 2025. The corporate cites native caching as “the popular technique providing a smoother buyer expertise and diminished bandwidth for all contributors.”


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