The Stripe webhook tool for cancellation feedback.

What the webhook handler looks like (build-it-yourself)

If you'd rather build the pipeline yourself, here's the shape of it. ChurnNote does this for you, but the code is helpful for understanding what's happening under the hood.

// /api/webhooks/stripe
import Stripe from 'stripe'

const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!)

export async function POST(req: Request) {
  const body = await req.text()
  const sig = req.headers.get('stripe-signature')!

  // 1. Verify the webhook
  const event = stripe.webhooks.constructEvent(
    body, sig, process.env.STRIPE_WEBHOOK_SECRET!,
  )

  if (event.type === 'customer.subscription.deleted') {
    const sub = event.data.object as Stripe.Subscription

    // 2. Look up the customer
    const customer = await stripe.customers.retrieve(sub.customer as string)

    // 3. Send the exit email (Resend / SES / Postmark)
    await sendExitEmail({
      to: (customer as Stripe.Customer).email!,
      from: 'you@yourdomain.com',
      subject: 'quick question',
      body: writePersonalEmailBody(customer, sub),
    })

    // 4. Set up inbound parser to capture the reply
    //    (out of scope for this snippet — see Resend Inbound)

    // 5. When reply lands, group the reason
    //    (this is the part most teams skip and regret)
  }

  return new Response('ok', { status: 200 })
}

What this snippet doesn't show: signature rotation, retry handling, inbound email parsing, threading replies to the original email, an AI step to group the reason, deliverability tuning, suppression handling. Those are the parts that make this a multi-week project rather than an afternoon.

What ChurnNote handles for you

1. 1

   Subscribe to customer.subscription.deleted

   In your Stripe dashboard, register a webhook endpoint and select the customer.subscription.deleted event. Stripe will POST to your endpoint every time a subscription is cancelled.

2. 2

   Verify the webhook signature

   Stripe signs every webhook with your webhook secret. Use stripe.webhooks.constructEvent(body, sig, secret) to verify the payload before processing — never trust unsigned requests.

3. 3

   Look up the customer email

   The webhook gives you a subscription object with a customer ID. Call stripe.customers.retrieve(id) to get the email and any metadata you stored on the customer.

4. 4

   Send the cancellation email

   Use a transactional sender (Resend, SES, Postmark, SendGrid) to send a plain-text email from your domain. Keep it under five lines, ask one open question, and use your real reply-to address.

5. 5

   Capture the reply

   Set up an inbound email parser (Resend Inbound, SendGrid Inbound Parse, or a forwarding rule into a webhook) so replies get ingested back into your system, not just sitting in your inbox.

6. 6

   Group the reason and store it

   Tag each reply by reason — pricing, missing feature, too complex, switched tool, bad experience, no longer needed — and store it on the customer record alongside their LTV and tenure. The tag drives win-back targeting later.

Steps 1–6 are what ChurnNote does the moment you connect Stripe. You don't write any handler code; you just paste an API key.

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