@alltuner/vacant — domain availability via authoritative DNS

JavaScript / TypeScript bindings for the vacant Rust engine. Asks the authoritative TLD nameservers directly instead of WHOIS — fast, no rate limits, no waiting.

The package ships the same Rust engine compiled in via napi-rs, with a small TypeScript facade and a vacant CLI entry point. Lockstep-versioned with the vacant crate: @alltuner/vacant 0.4.x wraps vacant 0.4.x (Rust) exactly.

Prefer a browser? vacant.alltuner.com is a hosted web UI built on vacant — a separate app that uses this package, not something it installs.

Install

Pick the path that matches how you'll use it:

CLI

brew install alltuner/tap/vacant   # macOS, Linux — native Rust binary
cargo install vacant               # any platform with a Rust toolchain
npx -y @alltuner/vacant google.com # one-shot, no install (Node wheel)

The brew / cargo paths give you the native Rust binary (instant startup, ideal for daily use). npx runs the Node package — convenient when you don't want a global install, slightly slower to start because it boots Node.

MCP server

Expose vacant to AI agents over the Model Context Protocol (stdio):

npx -y @alltuner/vacant mcp

It registers one tool — check_domains(domains, verify=false) — returning a {domain, status} per input. Point any MCP client at it:

{ "mcpServers": { "vacant": { "command": "npx", "args": ["-y", "@alltuner/vacant", "mcp"] } } }

Library

npm install @alltuner/vacant
# or
pnpm add @alltuner/vacant

import { checkMany, Status } from '@alltuner/vacant'

const results = checkMany(['example.com', 'anthropic.com', 'totally-made-up-zxqv.cat'])
for (const r of results) {
  console.log(r.domain, r.status, r.detail)
}

The on-disk SQLite cache is shared with the Rust CLI — runs against the same ~/.cache/vacant/results.db, so the brew binary and a Node script see each other's results.

import { DiskCache, checkMany } from '@alltuner/vacant'

const cache = new DiskCache() // default ~/.cache/vacant/results.db
const results = checkMany(['example.com'], { cache })

How it works

checkMany calls into the Rust engine via napi-rs. The engine:

1. Normalizes the input.
2. Looks up cache; returns hits immediately.
3. Runs a per-zone precheck (length, charset, reserved labels) from the bundled rules.toml.
4. For inputs that pass, asks the parent zone's NS directly. Delegation → registered; NXDOMAIN/NODATA → unconfirmed (not delegated, not verified). Pass { verify: true } to confirm unconfirmed names against the registry's RDAP endpoint, promoting them to available (404) or registered (200, e.g. a held domain). available only ever means RDAP-confirmed.

available is not a registrability guarantee, though: new gTLD registries (especially community/city zones like .barcelona, .cat, .amsterdam, .berlin) keep reservation and premium lists invisible to DNS, WHOIS, and RDAP, so a name can read available yet still be refused at checkout (e.g. radio.barcelona). Tracked for an in-engine fix in #26.

Cache shape, rules format, and verdict semantics are all the engine's — see alltuner/vacant for the source of truth.

Supported platforms

Prebuilt binaries ship for:

• darwin-arm64 (Apple silicon)
• darwin-x64 (Intel macs)
• linux-arm64-gnu
• linux-x64-gnu

npm picks the right one via optionalDependencies at install time. Other platforms aren't supported in v1; build from source via the Rust crate (cargo install vacant) if you need them.

Develop

The Node package lives in the alltuner/vacant monorepo alongside the Rust engine, so dev commands run from the repo root:

just                 # menu
just js-develop      # build the napi-rs extension into js/
just js-check        # tsc + node:test smoke
just js-pack         # produce a publishable tarball

License

MIT — see ../LICENSE.