robotwebtools/rosbridge_suite is a collection of bridge servers that expose the topics and services of ROS (Robot Operating System) through JSON (JavaScript Object Notation). It is a server implementation of the rosbridge v2 protocol, i.e. the second-generation specification, letting external clients publish and subscribe to ROS topics (message channels) or call ROS services by sending JSON messages. It supports WebSocket and TCP as transport layers.
This repository's place is that of a runtime connectivity layer between ROS and web applications. It is the conduit through which external apps communicate with robot topics and services: rosbridge_library provides a Python API that controls ROS publishers/subscribers and service calls according to JSON strings, rosbridge_server exposes this API as a WebSocket server, and rosapi provides service calls for querying ROS meta-information and interacting with the Parameter Server. The implementation language is Python, the license is BSD-3-Clause, and the GitHub star count is 1252.
However, the current state is hard to judge from the description the repository itself provides. The README only lays out the components and transport layers, and contains no performance figures or use-case comparisons, nor any information about the latest release. The fact alone that the project was created on October 16, 2012 does not tell us whether it is still maintained. If you are considering adding a ROS bridge layer, it is worth checking the repository's recent commits and issues first.