{"product_id":"n8n-workflow-fill-cancelled-appointments-via-waitlist-sheets-calendar-twilio","title":"n8n Workflow: Fill Cancelled Appointments via Waitlist (Sheets, Calendar, Twilio)","description":"\u003ch3\u003eInstantly fill cancelled appointments from your waitlist—automatically\u003c\/h3\u003e\n\u003cp\u003eThis n8n workflow watches your Google Sheets appointments for cancellations, then texts waitlist candidates via Twilio with a one-tap confirmation link to claim the newly opened slot. If someone confirms within 20 minutes, it books them in Google Calendar and updates both Google Sheets tabs—otherwise it moves on, or notifies the owner if the slot can’t be filled.\u003c\/p\u003e\n\n\u003ch3\u003eWhat this workflow does\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMonitors cancellations in Google Sheets:\u003c\/strong\u003e Polls the \u003cem\u003eAppointments\u003c\/em\u003e tab every 5 minutes and processes updated rows.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNormalizes appointment timing:\u003c\/strong\u003e Converts Google Sheets date\/time serial values into ISO date\/time strings and calculates a 30-minute end time.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTriggers only for “Cancelled” slots:\u003c\/strong\u003e Continues only when the appointment status is \u003cem\u003eCancelled\u003c\/em\u003e and the row has not been marked as waitlist-processed (then flags it as processed in Sheets).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIterates through matching waitlist candidates:\u003c\/strong\u003e Searches the \u003cem\u003eWaitlist\u003c\/em\u003e tab for entries in a \u003cem\u003eWaiting\u003c\/em\u003e status that match the cancelled appointment’s service type, offering candidates one-by-one.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOffers the slot via Twilio SMS:\u003c\/strong\u003e Marks each candidate as \u003cem\u003eOffered\u003c\/em\u003e, sends an SMS with a confirmation link, and waits up to \u003cstrong\u003e20 minutes\u003c\/strong\u003e for the link to be opened.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBooks on confirmation:\u003c\/strong\u003e If confirmed, creates the event in \u003cstrong\u003eGoogle Calendar\u003c\/strong\u003e, appends a new \u003cem\u003eFilled - Waitlist\u003c\/em\u003e row in \u003cem\u003eAppointments\u003c\/em\u003e, updates the waitlist entry to \u003cem\u003eBooked\u003c\/em\u003e, and sends a final Twilio confirmation SMS.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExpires and escalates:\u003c\/strong\u003e If not confirmed in time, marks the candidate as \u003cem\u003eExpired\u003c\/em\u003e and tries the next. If no one confirms, marks the original appointment \u003cem\u003eCancelled - Unfilled\u003c\/em\u003e and texts the owner via Twilio.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUse cases\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eClinics, tutoring services, salons, or any business with recurring appointment slots and a waitlist\u003c\/li\u003e\n  \u003cli\u003eReducing downtime from cancellations by rapidly filling open times\u003c\/li\u003e\n  \u003cli\u003eOperators who want an n8n-driven, spreadsheet- and calendar-based scheduling workflow\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical details\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGoogle Sheets:\u003c\/strong\u003e Reads and updates \u003cem\u003eAppointments\u003c\/em\u003e and \u003cem\u003eWaitlist\u003c\/em\u003e tabs\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGoogle Calendar:\u003c\/strong\u003e Creates the confirmed appointment event\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTwilio:\u003c\/strong\u003e Sends SMS messages and handles one-tap confirmations with a 20-minute wait window\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003en8n nodes\/logic mentioned:\u003c\/strong\u003e \u003cem\u003eif\u003c\/em\u003e, \u003cem\u003ecode\u003c\/em\u003e, \u003cem\u003ewait\u003c\/em\u003e, \u003cem\u003efilter\u003c\/em\u003e, \u003cem\u003etwilio\u003c\/em\u003e, \u003cem\u003esticky note\u003c\/em\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"N8N Commerce","offers":[{"title":"Default Title","offer_id":45812013826227,"sku":"N8N-17957","price":28.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0749\/6279\/6723\/files\/5EtI1PfqQZaDcfppoQ2Y-_UDfaFmCZ.png?v=1786353145","url":"https:\/\/buyflowscripts.com\/products\/n8n-workflow-fill-cancelled-appointments-via-waitlist-sheets-calendar-twilio","provider":"N8N Commerce","version":"1.0","type":"link"}