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ChurnKitOptions

const churn = new ChurnKit({
  apiKey: string           // required
  env?: 'production' | 'staging'
  baseUrl?: string
  timeout?: number
  maxRetries?: number
  onRequest?: (ctx: RequestContext) => void | Promise<void>
  onResponse?: (ctx: ResponseContext) => void | Promise<void>
})

​
Options reference

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apiKey required

Your FlowsBuilt API key. Get one from the Console. 
new ChurnKit({ apiKey: 'ck_live_abc123' })

​
env

Target API environment. Defaults to 'production'.
ValueAPI endpoint
'production'https://churnkit-api.vguruprasad91.workers.dev
'staging'https://churnkit-api-dev.vguruprasad91.workers.dev
// Use staging in development
new ChurnKit({ apiKey: 'ck_test_...', env: 'staging' })

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baseUrl

Override the API base URL entirely — takes precedence over env. Useful for self-hosted or proxy setups. 
new ChurnKit({ apiKey: '...', baseUrl: 'https://my-proxy.internal/churnkit' })

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timeout

Request timeout in milliseconds. Default: 15000 (15 seconds). 
new ChurnKit({ apiKey: '...', timeout: 5000 }) // fail fast after 5s

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maxRetries

Maximum number of attempts for retryable failures (network errors, 429, 5xx). Default: 3.
  • 1 = no retries (fail fast — use for non-idempotent writes if needed)
  • 5 = extra durability for high-stakes calls
new ChurnKit({ apiKey: '...', maxRetries: 1 }) // disable retries
Retries use exponential backoff with jitter.

​
onRequest

Called once before the first HTTP attempt. Use it to inject trace IDs, correlation IDs, or log outgoing requests.
onRequest fires once per SDK call — not on each retry. Mutations to ctx.headers apply to all retry attempts.
import { trace } from '@opentelemetry/api'

new ChurnKit({
  apiKey: '...',
  onRequest: (ctx) => {
    ctx.headers['X-Request-Id'] = crypto.randomUUID()
    ctx.headers['X-Trace-Id'] = trace.getActiveSpan()?.spanContext().traceId ?? ''
  },
})

​
onResponse

Called after every HTTP response, including each retry attempt. Use it to record per-attempt latency metrics. 
new ChurnKit({
  apiKey: '...',
  onResponse: (ctx) => {
    metrics.histogram('churnkit.latency', ctx.durationMs, {
      status: ctx.status,
      method: ctx.method,
      attempt: ctx.attempt,   // 0 = first, 1 = first retry, etc.
    })
    if (ctx.attempt > 0) {
      logger.warn('ChurnKit retry', { attempt: ctx.attempt, url: ctx.url })
    }
  },
})

​
Full example

import ChurnKit from '@vgpprasad91/churnkit-sdk'
import { trace } from '@opentelemetry/api'

export const churn = new ChurnKit({
  apiKey: process.env.CHURNKIT_API_KEY!,
  timeout: 10_000,
  maxRetries: 3,
  onRequest: (ctx) => {
    ctx.headers['X-Request-Id'] = crypto.randomUUID()
    ctx.headers['X-Trace-Id'] = trace.getActiveSpan()?.spanContext().traceId ?? ''
  },
  onResponse: (ctx) => {
    console.log(`[ChurnKit] ${ctx.method} ${ctx.url} → ${ctx.status} in ${ctx.durationMs}ms (attempt ${ctx.attempt})`)
  },
})