In Apigee Hybrid, the Synchronizer's primary job is to poll and download the runtime contracts which will be supplied by the management plane. Information communicated by contract includes API proxies, API products, caches, virtual hosts, and more.

Synchronizer instances running in the runtime-plane are expected to poll the management plane on a regular basis, download the contracts and make the same available to local runtime instances.

One Synchronizer can support many Message Processors deployed in the same pod.