Installation

Build the nstd executable from source and check that it works.

There is no download yet. No prebuilt nstd binary is published, so for now you build it from source. (The nstdlib package on npm is the standard library on its own, not this executable.)

#What you need

Zig 0.16.0. This exact version is required.
Node.js 26.10.0, the version in the repository's .nvmrc. The build reads details out of the Node it runs under, so a different version produces a broken build without warning. If your default node is another version, install a matching one and use it for these steps.
pnpm, through Corepack. Running corepack enable is enough if you don't already have it.
Git, which the setup step uses to download Node's source code.

#Build from source

Clone the repository:

git clone https://github.com/unjs/nstd.git
cd nstd

Install dependencies and download Node's source, which the build reads from:

corepack enable
pnpm install
pnpm setup:node

pnpm setup:node fetches only the parts of Node's source the build needs (about 136 MB) into ./node. Running it again does nothing once it's up to date.

Build the standard library. This produces ./dist, which gets embedded into the executable:

pnpm build

Then build the executable itself:

pnpm --filter nstdlib-native build

The finished binary is at native/zig-out/bin/nstd.

Tip

Use the pnpm script rather than running zig build directly. A plain zig build produces an unoptimized debug binary, which is only useful when you're tracking down a crash inside the Zig host.

#Check that it works

./native/zig-out/bin/nstd -e 'console.log(1 + 1)'
./native/zig-out/bin/nstd --print-realm

The first command should print 2. The second lists the Node builtin modules (fs, http, path and so on) that loaded in this build. Every one of them should be listed as available, with none missing.

Now try one of your own scripts:

./native/zig-out/bin/nstd my-script.js

#Build for WebAssembly (WASI)

You can also build nstd as a WebAssembly module. It boots the same standard library as the native build:

pnpm --filter nstdlib-native build:wasm

This produces native/zig-out/bin/nstd.wasm, which runs under any WASI-compatible runtime, such as wasmtime:

wasmtime native/zig-out/bin/nstd.wasm -- --print-realm

A few things behave differently in this build:

There is no outside network. WASI has no sockets, so net and http run on an in-memory network inside the program instead. A server and a client in the same program can talk to each other, but connecting to any other address fails with ECONNREFUSED, and hostname lookups fail too.
fs.watch() doesn't work. It needs Linux's inotify, so it throws. The error code currently reads UNKNOWN rather than ENOSYS, because WASI numbers its errors differently from Linux.

Everything else works the same as in the native build.

The WASI build is also a step toward running nstd in a browser, though not the final form of it. Exiting the process, waiting for events and file access still assume a WASI host and will need browser versions.

#Next steps

Once you have a working binary, Running Code shows how to use it, and CLI Options lists every flag it accepts.

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