llms.txt

# SxfeScript and SXN

> SxfeScript is JavaScript with an explicit safe/unsafe boundary, affine values and lexical borrows, plus erasable TypeScript annotations, all parsed natively with no build step. It runs on ArcSX, a QuickJS-based runtime built as `sxn` that is designed to run the same on a phone as it does on a server.

ArcSX implements the WinterCG web APIs (fetch, Sxn.serve, Web Streams, Web Crypto) and a Node compatibility layer (CommonJS, node: builtins, .node native addons). It has no JIT, deliberately: iOS will not grant a third-party app the entitlement to generate machine code, and running there is the point.

- Source: https://github.com/SxfeScript/sxfescript
- Every page below, in full: https://sxfescript.github.io/llms-full.txt

## Get started

- [Quick start](https://sxfescript.github.io/docs/quickstart/): Install sxn, run your first .js, .ts and .sx file, and start an HTTP server.
- [Examples](https://sxfescript.github.io/docs/examples/): Complete programs you can run, each with the output it actually prints.
- [CLI reference](https://sxfescript.github.io/docs/cli/): Every sxn command and flag, and how a file with no extension is resolved.

## The language

- [Language contract](https://sxfescript.github.io/docs/language/): What .sx adds to JavaScript: erasable types, safe/unsafe, ownership, layout.
- [ABI](https://sxfescript.github.io/docs/abi/): The boundary between SxfeScript values and native memory.
- [Bytecode](https://sxfescript.github.io/docs/bytecode/): Compiling to .sxbc, the compile cache, the measured gains, and the trust boundary.

## The runtime

- [Runtime surface](https://sxfescript.github.io/docs/runtime/): The WinterCG web APIs and the Sxn host namespace: fetch, Sxn.serve, streams, crypto, FFI.
- [Node compatibility](https://sxfescript.github.io/docs/node/): CommonJS, the node: builtins, and .node native addons through a from-scratch Node-API.
- [Native code](https://sxfescript.github.io/docs/native/): Sxn.ffi and .node addons, and why only one of the two belongs to the engine.
- [Networking](https://sxfescript.github.io/docs/network/): The networking primitives the runtime is built on.

## Project

- [Performance](https://sxfescript.github.io/docs/performance/): The full benchmark write-up: methodology, both machines, and every optimization behind the numbers.
- [Benchmark references](https://sxfescript.github.io/docs/benchmark-references/): Where the comparison numbers come from.
- [Implementation ledger](https://sxfescript.github.io/docs/implementation/): What is real today and what is not yet, kept honest and up to date.
- [Contributing](https://sxfescript.github.io/docs/contributing/): What is genuinely open to debate, and the one constraint that is not.
- [Project README](https://sxfescript.github.io/docs/readme/): The overview, the install commands, and the two benchmark tables.