Comparison to similar systems

The Envoy Mobile proposed roadmap has similarities to several existing systems. They are compared below.


The projects below are under active development. Thus some of the information may become out of date. If that is the case please let us know and we will fix it.


Cronet is Google’s cross-platform client networking library that is used by all of its mobile applications and several other companies including Snap. In terms of goals, Cronet is a subset of Envoy Mobile targeted at advanced client networking protocols, with the caveat that it already supports QUIC. Envoy Mobile’s goals are larger and include extensibility, observability, IDL integration, etc. With that said, there is a lot to learn from Cronet in terms of how it handles QUIC in a robust and production ready way.

proxygen and mvfst

proxygen is Facebook’s high performance HTTP proxy library, written on top of a Finagle like C++ library called wangle. mvfst is Facebook’s recently open sourced QUIC implementation. Both libraries are used by Facebook in their mobile applications, but none of the mobile integration code has been open sourced. Like Cronet, Envoy Mobile’s goals are a superset of what proxygen and mvfst provide.


gRPC is a multi-platform message passing system out of Google. It uses an IDL to describe an RPC library and then implements application specific runtimes for a variety of different languages. The underlying transport is HTTP/2. gRPC does have mobile client libraries, though the production readiness is not equivalent to the server-side libraries. In terms of goals and feature set, gRPC is closer to Envoy Mobile than Cronet or proxygen/mvfst, and in fact gRPC is currently in the process of migrating its look-aside load balancing APIs to xDS. It is possible that in the future gRPC’s mobile clients will continue to converge with Envoy Mobile, but in the near term we feel that Envoy Mobile can deliver a production ready iOS/Android feature set that includes xDS, QUIC, etc. in a shorter time frame. Note that Envoy Mobile will likely continue to use gRPC framing for calling IDL based unary and streaming APIs, making it wire compatible with gRPC on the server.