ES-Runtime

V8-based ECMAScript runtime, WinterTC-compliant, I/O-injectable, capability-secured.

Website & docs → esrun.opentechf.org

It ships in two shapes from the same core:

• Embeddable library (es-runtime) — a driven (tick/poll) runtime with all I/O injected via provider traits and V8 kept behind an engine abstraction.
• Standalone CLI (esrun) — a thin binary that wires the default tokio providers and runs JavaScript files end-to-end.

Install

A prebuilt, checksum-verified binary:

Linux / macOS:

curl -fsSL https://raw.githubusercontent.com/Open-Tech-Foundation/ES-Runtime/main/install.sh | bash

Windows (PowerShell):

irm https://raw.githubusercontent.com/Open-Tech-Foundation/ES-Runtime/main/install.ps1 | iex

Or build from source — a single self-contained binary at target/release/esrun, no extra files or asset directory:

cargo build --release -p es-runtime-cli   # or the alias: cargo build-cli

Run JavaScript

Run JS files like node/bun:

esrun examples/hello.js
esrun examples/modules/main.mjs   # ES module: import/export + top-level await
esrun -e "console.log(6 * 7)"
esrun --help

(If you built from source, the binary is at ./target/release/esrun. To call it as esrun from anywhere, run cargo install --path crates/runtime-cli.)

The full implemented WinterTC surface is available (console, URL, fetch, crypto, streams, encoding, timers, events); all host capabilities are granted. Inputs run as ES modules: static import/export, dynamic import(), import.meta.url, and native top-level await all work. Imports resolve as local files (relative or absolute paths, or file: URLs) and bare specifiers through node_modules for ES module packages (run npm install yourself — nothing is fetched). CommonJS packages and node: builtins are rejected with a clear message; import attributes and remote modules are not supported yet.

TypeScript

esrun doesn't execute TypeScript, but it ships editor types for the runtime:* modules:

esrun types --install   # writes the defs into node_modules/@opentf/esrun and wires tsconfig.json

esrun types alone prints them to stdout. See esrun.opentechf.org/docs/typescript.

Documentation

• esrun.opentechf.org — full docs, guides, and cross-runtime benchmarks.
• API reference — globals, scope/non-goals, the runtime: modules and their exports (canonical).

Development

Build, test, and benchmark from source:

Task	Command
Build everything (lib + CLI)	cargo build-all
Build just the esrun binary	cargo build-cli
Run tests	cargo test --workspace
Lints + format check	cargo clippy --workspace --all-targets -- -D warnings · cargo fmt --check
Supply-chain gates	cargo deny check · cargo audit
Startup/throughput microbenchmark	cargo run --release -p es-runtime-default-providers --example bench
Cross-runtime benchmark	bench/run.sh (see bench/README.md)

License

Licensed under the Apache License, Version 2.0. See the NOTICE file for attribution.

ES-Runtime
Copyright 2026 Open Tech Foundation <https://opentechf.org> and its contributors