SnapPDF + Stripe

What you can build

• Listen to `invoice.paid`, `invoice.finalized`, `charge.refunded`, `checkout.session.completed`.
• Merge Stripe's auto-generated invoice with your cover page, terms, and receipt PDFs.
• Stamp PAID / REFUNDED / OVERDUE based on event type.
• Compress to <1MB for Gmail-safe attachment delivery.
• Emit a SnapPDF webhook on completion so downstream services (Resend, SES, HubSpot) can finalize.

Setup

1. 01
   Configure Stripe webhook

   Stripe dashboard → Developers → Webhooks → Add endpoint. URL: `https://api.snappdf.dev/api/v1/webhooks/stripe` (or your own handler).
2. 02
   Select events

   Pick `invoice.paid`, `invoice.finalized`, `charge.refunded`, `checkout.session.completed`. Fewer events = less quota burn.
3. 03
   Copy the webhook signing secret

   Stripe shows the `whsec_…` signing secret. Paste it into SnapPDF dashboard → Integrations → Stripe.
4. 04
   Configure the flow

   SnapPDF dashboard → Stripe flow editor. Pick: merge with cover? apply watermark? compress? email via Resend?
5. 05
   Link your Stripe account (optional)

   Use Stripe Connect to let SnapPDF read invoice PDFs directly — avoids needing you to provide a URL.
6. 06
   Test with Stripe CLI

   `stripe trigger invoice.paid` against your endpoint. Verify the final PDF lands in the test customer's inbox.

Code example

Raw Stripe webhook handler wiring — what the integration does under the hood.

import Stripe from 'stripe';
import { SnapPDF } from '@snappdf/sdk';

const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!);
const snap = new SnapPDF({ apiKey: process.env.SNAPPDF_KEY! });

export async function POST(req: Request) {
  const sig = req.headers.get('stripe-signature')!;
  const event = stripe.webhooks.constructEvent(
    await req.text(),
    sig,
    process.env.STRIPE_WEBHOOK_SECRET!,
  );

  if (event.type !== 'invoice.paid') return new Response('ok');
  const inv = event.data.object as Stripe.Invoice;

  const { pdf: merged } = await snap.pdf.merge({
    files: [inv.invoice_pdf!, 'https://cdn.acme.com/legal/terms.pdf'],
  });
  const { pdf: stamped } = await snap.pdf.watermark({
    file: merged, kind: 'text', text: 'PAID',
    position: 'diagonal', opacity: 0.18, color: '#0f766e',
  });
  const { pdf: small } = await snap.pdf.compress({ file: stamped, level: 'high' });

  await resend.emails.send({
    to: inv.customer_email!,
    from: 'billing@acme.com',
    subject: `Invoice ${inv.number} — Paid`,
    attachments: [{ filename: `${inv.number}.pdf`, content: small }],
  });

  return new Response('ok');
}

FAQ

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