Fill cancelled booking slots from a ranked waitlist using webhooks and SMS/WhatsApp

by Vlotstroom ✓ · 1 views · created 2026-10-12 · Project Management

What this workflow does

This workflow has 20 nodes and runs when an HTTP POST request hits its webhook URL (plus 2 other triggers). It uses only n8n's built-in nodes.

How it runs

Trigger: When an HTTP POST request hits its webhook URL (plus 2 other triggers).

1. Normalize cancellation (Code): runs custom JavaScript code
2. Valid claim body? (Code): runs custom JavaScript code
3. Sweep: expired slots (Code): runs custom JavaScript code
4. Valid? (If): checks a condition and branches into true / false
5. Claim valid? (If): checks a condition and branches into true / false
6. Waitlist (demo data) (Code): runs custom JavaScript code
7. Respond invalid (Respond to Webhook): sends the response back to the webhook caller
8. Claim guard (first TAKE wins) (Code): runs custom JavaScript code
9. Respond claim invalid (Respond to Webhook): sends the response back to the webhook caller
10. Rank + build offers (Code): runs custom JavaScript code

…plus 7 more steps. See the full node list below.

Before you upgrade to n8n 3.0

Nodes used (5)

• Webhookn8n-nodes-base.webhook
• Coden8n-nodes-base.code
• Ifn8n-nodes-base.if
• Respond to Webhookn8n-nodes-base.respondToWebhook
• Schedule Triggern8n-nodes-base.scheduleTrigger

From the author

Quick overview This workflow fills cancelled slots automatically: the top three waitlist matches get an offer at once, the first reply wins atomically, and a 30-minute sweeper re-offers expired or declined slots to the next people until the list runs out. How…

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