Notifications

Seshn + Slack

Post booking notifications to Slack channels. New bookings, cancellations, payment alerts — right where your team already works.

Setup

No SDK required. Slack Incoming Webhooks accept a simple HTTP POST — you can wire this up with just fetch.

Go to your Slack workspace settings and create an Incoming Webhook.
Choose the channel (e.g. #bookings).
Copy the webhook URL.

Webhook events

Choose which events matter for your team's ops:

booking.createdNew booking notification

booking.cancelledAlert on cancellations

payment.failedPayment issues that need attention

waitlist.joinedDemand signal for popular slots

Webhook handler

app/api/webhooks/seshn/route.ts

1import { createHmac } from 'crypto';
2
3const SLACK_WEBHOOK_URL = process.env.SLACK_WEBHOOK_URL!;
4const WEBHOOK_SECRET = process.env.SESHN_WEBHOOK_SECRET!;
5
6export async function POST(req: Request) {
7  const body = await req.text();
8  const signature = req.headers.get('x-webhook-signature');
9
10  const expected = 'sha256=' +
11    createHmac('sha256', WEBHOOK_SECRET).update(body).digest('hex');
12
13  if (signature !== expected) {
14    return new Response('Invalid signature', { status: 401 });
15  }
16
17  const event = req.headers.get('x-webhook-event');
18  const payload = JSON.parse(body);
19
20  let text: string | null = null;
21
22  switch (event) {
23    case 'booking.created':
24      const date = new Date(payload.slot.startTime);
25      text = [
26        '*New booking*',
27        `>${payload.service.name}`,
28        `>${payload.contact.name} · ${payload.seats} seat(s)`,
29        `>${date.toLocaleDateString()} at ${date.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })}`,
30      ].join('\n');
31      break;
32
33    case 'booking.cancelled':
34      text = [
35        '*Booking cancelled*',
36        `>${payload.service.name}`,
37        `>${payload.contact.name}`,
38        payload.reason ? `>Reason: ${payload.reason}` : null,
39      ].filter(Boolean).join('\n');
40      break;
41
42    case 'payment.failed':
43      text = [
44        '*Payment failed*',
45        `>Booking ${payload.bookingId}`,
46        `>${payload.contact.name} · ${payload.contact.email}`,
47        `>Amount: ${(payload.amount / 100).toFixed(2)} ${payload.currency.toUpperCase()}`,
48      ].join('\n');
49      break;
50
51    case 'waitlist.joined':
52      text = [
53        '*Waitlist joined*',
54        `>${payload.service.name}`,
55        `>${payload.contact.name} is waiting for a spot`,
56      ].join('\n');
57      break;
58  }
59
60  if (text) {
61    await fetch(SLACK_WEBHOOK_URL, {
62      method: 'POST',
63      headers: { 'Content-Type': 'application/json' },
64      body: JSON.stringify({ text }),
65    });
66  }
67
68  return new Response('OK', { status: 200 });
69}

Register the webhook

terminal

1curl -X POST https://api.seshn.net/v1/webhooks \
2  -H "Authorization: Bearer sk_live_..." \
3  -H "Content-Type: application/json" \
4  -d '{
5    "url": "https://yourdomain.com/api/webhooks/seshn",
6    "events": [
7      "booking.created",
8      "booking.cancelled",
9      "payment.failed",
10      "waitlist.joined"
11    ]
12  }'

Next steps

Use Block Kit for richer message formatting with buttons and fields.
Route different events to different channels — e.g. #bookings for new bookings, #alerts for payment failures.
Add a daily digest using a cron job that queries GET /v1/bookings and posts a summary.