Google announced that it will discontinue support for the JSON-RPC protocol and Global HTTP Batch. As Google continues to invest in its API infrastructure, it must support the latest API technology, which continues to evolve quickly. Increased performance and enhanced security have led Google beyond these two technologies, and JSON- RPC and Global HTTP Batch are no longer compatible with Google's infrastructure moving forward.
"Our support for these features was based on an architecture using a single shared proxy to receive requests for all APIs," Shilpa Kamalakar, Google Technical Program Manager, commented in a blog post announcement. "As we move towards a more distributed, high performance architecture where requests go directly to the appropriate API server we can no longer support these global endpoints."
Although Google had originally planned to end support for both features last year, it has now extended the deadline. As of August 12 of this year, neither will be supported. Transitioning away from these features takes some development work, and associated downtime. To assist developers, Google has published a downtime schedule.
If you send requests to "https://www.googleapis.com/rpc" or "https://content.googleapis.com/rpc". you currently use JSON-RPC and need to migrate. If you form homogeneous batch requests using Google API Client Libraries or using non-Google API client libraries or no client Library (i.e making raw HTTP requests), you need to migrate. To see answers to most migration questions, visit the blog post announcement.