# `deno_runtime` crate
[](https://crates.io/crates/deno_runtime)
[](https://docs.rs/deno_runtime)
This is a slim version of the Deno CLI which removes typescript integration and
various tooling (like lint and doc). Basically only JavaScript execution with
Deno's operating system bindings (ops).
## Stability
This crate is built using battle-tested modules that were originally in `deno`
crate, however the API of this crate is subject to rapid and breaking changes.
## `MainWorker`
The main API of this crate is `MainWorker`. `MainWorker` is a structure
encapsulating `deno_core::JsRuntime` with a set of ops used to implement `Deno`
namespace.
When creating a `MainWorker` implementors must call `MainWorker::bootstrap` to
prepare JS runtime for use.
`MainWorker` is highly configurable and allows to customize many of the
runtime's properties:
- module loading implementation
- error formatting
- support for source maps
- support for V8 inspector and Chrome Devtools debugger
- HTTP client user agent, CA certificate
- random number generator seed
## `Worker` Web API
`deno_runtime` comes with support for `Worker` Web API. The `Worker` API is
implemented using `WebWorker` structure.
When creating a new instance of `MainWorker` implementors must provide a
callback function that is used when creating a new instance of `Worker`.
All `WebWorker` instances are descendents of `MainWorker` which is responsible
for setting up communication with child worker. Each `WebWorker` spawns a new OS
thread that is dedicated solely to that worker.