FastRPC — Binary XML-RPC

As Chose reported, the developers at Seznam.cz have added another project to the open-source family. FastRPC is XML-RPC that serializes data in binary for transmission.

That compact binary format is supposed to be what makes FastRPC special. Here’s how Chose puts it.

… the FastRPC protocol, which is most useful in high-load applications that need high performance, speed and as little unnecessary data on the wire as possible. That's possible because FastRPC is essentially a binary version of traditional XML-RPC.

That claim strikes me as debatable. I'd argue that XML-RPC is already a lightweight protocol and doesn't cause performance problems on its own. Switching from plain text to binary can cut the amount of data transferred, but it may introduce binary incompatibilities when serializing and deserializing on different systems. Interoperability is precisely why people prefer XML or plain text, at least until there's a binary XML standard. See Akta X 0309.

If the goal was to save bandwidth, why skip the standard features HTTP already offers? HTTP compression could substantially reduce the amount of data sent. I'd be very interested in a comparison between FastRPC and compressed XML-RPC. I'd also like to see how much of a performance gain binary XML-RPC delivers over traditional XML-RPC.