Web API Features
Web APIs are part of the core Jint package on .NET 8 and later. They are opt-in and install no globals unless requested.
var engine = new Engine(options => options.UseWebApis());UseWebApis() enables the non-network default set. Network access and persistent state require separate, explicit grants.
Measured conformance
Jint conforms to 62 of the 78 WinterTC Minimum Common API member outcomes (79.5%) after the explicit fetch grant is enabled. That total consists of 59 present members and three global event-handler properties that WinterTC requires this non-EventTarget global shape not to expose. The remaining 16 members are WebAssembly, which Jint declines by design because it would require a separate bytecode virtual machine.
The vendored .any.js web-platform-tests corpus passes 38,649 of 41,581 assertions (92.9%) across 44 selected suite directories representing 14 standards. It is a gated, Windows-measured subset rather than a claim about the complete web platform.
| Area | Examples | Default |
|---|---|---|
| Console and scheduling | console, timers, microtasks, scheduler, idle callbacks | Yes |
| Data | encoding, base64, blobs, files, streams, compression | Yes |
| Platform | events, URL, crypto, performance, navigator | Yes |
| Messaging | structured clone, message channels, broadcast channels | Yes |
| Storage | local and session storage | No |
| Networking | fetch, XHR, WebSocket, EventSource | No |
| Cache | Cache API with host-provided storage | No |
| Workers | Worker with a host-provided worker provider | No |
| Request handling | fetch events | No |
Dependencies between flags are expanded automatically. For example, fetch also installs the URL, files, streams, and events it needs.
See Web APIs for configuration and security guidance.