Installation

Requirements

Node.js 18+ (or any edge runtime with Web Crypto API)
TypeScript 5.0+ (optional but recommended)

Install

npm install @vgpprasad91/churnkit-sdk

yarn add @vgpprasad91/churnkit-sdk

pnpm add @vgpprasad91/churnkit-sdk

bun add @vgpprasad91/churnkit-sdk

Set your API key

Add your key to your environment:

.env

CHURNKIT_API_KEY=ck_live_your_key_here

Use ck_test_ keys in development and CI. Test keys are completely isolated from production data.

Basic setup

import ChurnKit from '@vgpprasad91/churnkit-sdk'

const churn = new ChurnKit({
  apiKey: process.env.CHURNKIT_API_KEY!,
})

Next.js setup

Create a shared client file so you don’t instantiate on every request:

lib/churnkit.ts

import ChurnKit from '@vgpprasad91/churnkit-sdk'

// Module-level singleton — instantiated once per server process
export const churn = new ChurnKit({
  apiKey: process.env.CHURNKIT_API_KEY!,
})

Then import churn in your Server Actions, Route Handlers, or API routes:

app/api/checkout/route.ts

import { churn } from '@/lib/churnkit'

export async function POST(req: Request) {
  const { userId } = await req.json()
  await churn.event(userId, 'checkout_started')
  // ...
}

Cloudflare Workers / Edge

The SDK uses only Web-standard APIs (fetch, crypto.subtle) and works on Cloudflare Workers, Vercel Edge Functions, and Deno Deploy with no modifications:

worker.ts

import ChurnKit from '@vgpprasad91/churnkit-sdk'

export default {
  async fetch(request: Request, env: Env) {
    const churn = new ChurnKit({ apiKey: env.CHURNKIT_API_KEY })
    await churn.event('user_123', 'page_viewed')
    return new Response('ok')
  },
}

Module formats

The package ships both ESM and CJS:

Format	Entry point
ESM	`dist/index.mjs`
CJS	`dist/index.cjs`
Types	`dist/index.d.ts`

import and require both work out of the box.

ChurnKit

Tracking Events

Churn Risk

Watching Users

Webhooks

Reference

Requirements

Install

Set your API key

Basic setup

Next.js setup

Cloudflare Workers / Edge

Module formats

​Requirements

​Install

​Set your API key

​Basic setup

​Next.js setup

​Cloudflare Workers / Edge

​Module formats

Requirements

Install

Set your API key

Basic setup

Next.js setup

Cloudflare Workers / Edge

Module formats