The remote API is part of the V-REP API framework. It allows communication between V-REP and an external application (i.e. an application running in a different process, or on a different machine), is cross-platform, and supports service calls (i.e. blocking calls), and bidirectional data streaming. It comes in two distinct versions/frameworks:
The B0-based remote API: this represents the second version of the remote API. It is based on the BlueZero middleware and its interface plugin to V-REP. It is easier and more flexible to use than the legacy remote API, and most importantly, it is easy to extend. It currently supports following languages: C++, Java, Python, Matlab and Lua.
The legacy remote API (or simply remote API): this represents the first version of the remote API. It is comparatively lightweight and has less dependencies than the B0-based remote API. It is however less intuitive and less flexible, and more difficult to extend. It supports following languages: C/C++, Java, Python, Matlab, Octave and Lua.
V-REP API framework
The B0-based remote API
The legacy remote API