Vein

Vein is a lightweight RPC (Remote Procedure Call) library for Node.js and the browser that uses WebSockets for communication. The current stable version is 0.5.5, released in 2012, with no recent updates and no release cadence. It provides a simple server-client model where the server registers services (e.g., 'multiply') and clients can call them as if they were local functions. Key differentiators include built-in middleware support for authentication and authorization, and a callback-first pattern. However, Vein has been unmaintained for over a decade and relies on ES5 features, requiring an es5-shim for older browsers. It is primarily suited for hobby or legacy projects, not production use.