Prebid Video Cache

Nexx360 operates a hosted, Prebid Cache-compatible service that stores winning VAST creatives at auction time and serves them back to video players via a short URL. The public endpoint is https://fast.nexx360.io/pb/cache.

It is a drop-in replacement for the legacy AppNexus Prebid Cache (https://prebid.adnxs.com/pbc/v1/cache) — only the cache.url value in your Prebid.js configuration changes.

Why a video cache?

Most ad servers (Google Ad Manager in particular) and most video players accept a VAST URL, not raw VAST XML. Header bidding produces VAST creatives at auction time, so Prebid.js needs somewhere addressable to park them before passing a reference to the ad server.

The end-to-end flow:

1. A bidder returns a VAST XML payload to Prebid.js.

2. Prebid.js POSTs the VAST to https://fast.nexx360.io/pb/cache and receives a UUID.

3. The UUID is written into GAM key-values (hb_uuid, hb_cache_id, hb_cache_host, hb_cache_path).

4. The GAM video creative builds a cache URL (https://fast.nexx360.io/pb/cache?uuid=…) and serves it to the player.

5. The player issues a GET on the cache URL to retrieve the VAST XML and start playback.

See the Prebid video overview for the canonical explanation.

If a bidder caches its own creative and returns bidResponse.videoCacheKey, Prebid skips the cache step for that bid. The cache is only used for bidders that hand back raw VAST.

Configure Prebid.js

Set the cache URL in pbjs.setConfig:

pbjs.setConfig({
    cache: {
        url: 'https://fast.nexx360.io/pb/cache?account_id=XXXX'
    }
});

Replace XXXX with your Nexx360 account ID.

account_id is a tagging convention used for log correlation across the Nexx360 stack. The cache service itself does not validate it, but you should still include it so support can trace your traffic.

Other useful options on the cache config object:

Option	Description
ignoreBidderCacheKey	Force re-wrapping of bidder-supplied keys so every VAST sits behind one cache URL
useLocal	Store VAST as a browser blob instead of calling the remote cache
batchSize	Batch multiple puts into a single POST
batchTimeout	Maximum wait time in ms before flushing a batch
timeout	Request timeout in ms

Full reference: Prebid.js setConfig.

Retrieving cached VAST in GAM creatives

The cache URL pattern used in GAM creatives (hb_cache_host + hb_cache_path + hb_cache_id) is documented in the GAM setup pages alongside the full creative snippet:

Google Ad Manager Setup

For questions about cache configuration or migration from AppNexus, contact [e-mail].