Jint

Web APIs ​

Jint provides an opt-in, WHATWG-oriented web platform surface for scripts that need APIs such as console, timers, events, encoding, streams, fetch, storage, or workers. Web APIs require .NET 8 or later.

csharp
var engine = new Engine(options => options
    .UseWebApis(WebApiFeatures.Console | WebApiFeatures.Timers)
    .UseConsole(Console.Out));

Nothing is installed by default. UseWebApis() enables the default non-network, non-persistent set; outbound networking, storage, caches, script-registered inbound handlers, and workers require separate grants. Installation is lazy, non-clobbering, and limited to the principal realm.

Jint never starts a thread to run script. Timers, messages, network completions, and worker communication move only while the owning engine is pumped. Enabling fetch, sockets, or event streams gives script the process's network position: restrict destinations and sizes, partition state per tenant, and apply execution constraints. Jint remains an in-process library, not a security boundary.

Topics ​