@checkgate/node

Checkgate Node.js SDK (NAPI) — The official high-performance, native Node.js client for Checkgate. This SDK is built on top of the Rust native codebase, powered by NAPI-RS for absolute zero-overhead sub-microsecond feature flag evaluation directly in your server.

Installation

npm install @checkgate/node
# or
pnpm add @checkgate/node
# or
yarn add @checkgate/node

Quick Start

Initialize the Checkgate client with your unique server URL and SDK key:

import { CheckgateClient } from '@checkgate/node'

const checkgate = new CheckgateClient({
  serverUrl: 'http://localhost:3000', // Your self-hosted Checkgate server URL
  sdkKey: 'sk_prod_xxxxxxxx',         // Your secure server-side SDK Key
})

async function run() {
  // Connect via SSE to instantly stream flag rules
  await checkgate.connect()

  // Evaluate features with sub-microsecond latency locally
  const showFeature = checkgate.isEnabled('new-dashboard', 'user_123', { 
    email: '[email protected]' 
  })

  if (showFeature) {
    console.log("Welcome to the new dashboard!")
  }
}

run()

A/B testing: track conversions

Record goal events with track() to measure how each flag variant converts. Pair a flag with a goal event in an Experiment in the dashboard to see per-variant conversion rates and statistical significance.

const variant = checkgate.getVariant('checkout-button-color', 'user_123')

// …later, when the user converts:
checkgate.track('checkout_complete', 'user_123', { value: 49.99 })

Events are buffered and reported asynchronously (best-effort), just like impressions. Use the same userKey you pass to getVariant()/isEnabled() so conversions attribute to the right variant.

Why Checkgate?

• Sub-Microsecond Evaluation: Flags are parsed instantly in-memory via Rust native bindings.
• Instant Propagation: Leverages SSE (Server Sent Events) to distribute flag toggles globally in < 50ms without polling.
• Self-Hosted Privacy: Keep your user data strictly within your own infrastructure bounds.

For more information and detailed architecture designs, check out the official Checkgate documentation.