Academy › Build › WhatsApp and customers
The exact minute they left
By the end, you'll have decided which unfinished action triggers the message and how long to wait before sending it, depending on whether it's a booking or an order.
By Yodai · Published September 6, 2026 · Updated October 12, 2026
Someone lands on your site, opens up the Thursday 5 p.m. slot, and never confirms it. Or they drop a session package in the cart and close the tab before paying. They're gone. The question that decides everything in this course is this: at what exact moment do you call it abandoned, and how long do you wait before you message them?
It's not a small question. Warn too soon and the customer feels chased and closes the text without reading it. Warn too late and they've already booked with the place next door or forgot they even wanted this. The gap between those two mistakes is narrow, and today you're going to pin it down.
What counts as ghosting a customer
Not everyone who doesn't finish has drifted off the same amount. Someone who landed on the booking page and never even looked at the available times hasn't left you anything: there's no data, no one to message, and that doesn't count as abandonment for this sequence. The reminder only makes sense once the person has given you a phone number or email, because without that there's no one to message. And the number alone isn't enough. The WhatsApp Business Messaging Policy only lets you write to someone who has given you their number and also agreed to receive messages from you. In Spain, the Information Society Services Act defines a commercial communication as any form of communication that promotes, directly or indirectly, a business's products or services. Its Article 21 bans sending them by email or any equivalent electronic means without prior request or express consent. The exception is for someone who's already your customer, and only for products similar to what they bought. So get that permission in the same step where they leave their phone number.
That's why the trigger isn't they visited your site and left. The trigger is they reached the step where they entered their phone number, and stopped right there. For an appointment, that step is usually picking a time and entering a number to confirm. For an order, it's adding a product to the cart and reaching the checkout screen without finishing it. Don't reach out before that point: messaging someone who's only browsed prices burns the trust you'll need for the real reminder that comes later. And not everyone who stops does it for the same reason. In a study by the Baymard Institute of online shoppers in the United States, 42% had abandoned a cart at some point just because they were browsing or weren't ready to buy yet. Leaving those out, 40% abandoned it because of unexpectedly high extra costs, 19% because they didn't trust the site with their card, and 17% because the site had errors or crashed.
Why the waiting period can't be zero
You might think the sooner you send the reminder, the better: you catch the customer while the phone's still in their hand. It's actually the opposite. If the message lands three minutes after someone abandons a half-finished booking, they don't read it as a friendly nudge, they read it as "someone was watching me." And nobody responds to that feeling by booking, they respond by blocking the number. On WhatsApp, that matters: their business policy notes that users can block or report a business, and that those reactions can lead to limits on how many messages it's allowed to send. The data backs up that sending too soon costs you sales. In a study of online stores published in the Journal of Marketing, shoppers who got a cart reminder between 30 minutes and an hour after abandoning it bought less than those who got no reminder at all. But the reminder that arrived one to three days later did boost purchases, and the same held true for SMS reminders. And at checkout, the payment processor sets the clock: in Stripe Checkout, a payment session expires anywhere from 30 minutes to 24 hours after it's created, depending on what you set, and if you don't set anything, it defaults to 24 hours.
The window has to give them plenty of time to finish on their own
How the exact moment gets marked
- 1The customer leaves a detail
At the booking or checkout step, they enter their phone number or email. Without this there's no trigger: log the exact time they left it, not the time they landed on the site. - 2The window is counted from that moment
Never less than an hour. If it was an appointment, before the time they booked; if it was a cart, one to three days; and if they dropped off at checkout, when that session expires (in Stripe, 30 minutes to 24 hours). - 3If they haven't confirmed once the waiting period is up, it gets marked as abandoned
That's all this lesson covers: deciding the moment, not yet the message that gets sent. - 4The alert is triggered by that mark, not by a fixed time of day
It doesn't matter if it's three in the afternoon or eleven at night: what counts is the time elapsed since they left the detail, not the clock time.
Now that you've nailed down the timing, the next lesson covers what each reminder actually says: the first message isn't the same as the one that lands days later, and that's where the real work is. On WhatsApp, you're also the one starting that first message: if you send it through the WhatsApp Business Platform (the version built for software, not the mobile app), its Messaging Policy requires you to open the conversation with an approved template, and it only lets you write without a template within 24 hours of a message from the customer.
- Decided which point of abandonment triggers the sequence: leaving a phone number or email, not just landing on the page.
- Window set for an appointment: more than an hour, and before the time they booked.
- Window set for an order: one to three days; if they dropped off at checkout, when that session expires (in Stripe, 30 minutes to 24 hours), and never before an hour has passed.
- The trigger's clock counts from the detail left behind, not from the time they landed on the site.
Three cases to decide the trigger
Answer before opening each one. If one gives you trouble, go back to the section that explains it.
1. A customer lands on your appointment booking page, looks at the three open Thursday slots, and closes the tab without entering anything. Do you send the alert?
No. They didn't leave a phone number or email, so there's no one to write to. This doesn't count as abandonment for this sequence; it just counts as a visit.
2. Someone adds two session bundles to the cart at ten in the morning and doesn't pay. By one in the afternoon they still haven't confirmed. Has the window already passed?
Not yet. For an order, the window is one to three days from when they left their info, so three hours in is too soon: the first reminder should go out, at the earliest, tomorrow at 10 a.m.
3. A customer picked a time, entered their phone number, and five minutes later opened the deposit payment screen, but closed it without finishing. Which window do you use, the one for the appointment or the one for the dropped payment?
The one with the dropped payment, because they already left their info and made it to the checkout screen: you wait for that session to expire, which Stripe sets between 30 minutes and 24 hours. In Baymard's data (United States), the reasons people abandon a purchase midway include an extra cost, not trusting the site with their card, or the site failing. And even if you set a short expiration, don't send the reminder before an hour has passed: a reminder that soon costs you sales instead of winning them back.
You already know the exact minute to sound the alarm. What you haven't decided yet is how many times you'll knock on that door after the first one, and at what message you stop pushing altogether.
Sources
- WhatsApp Business Messaging Policy. WhatsApp (Meta), last updated September 23, 2026.
- Law 34/2002, of July 11, on Information Society Services and Electronic Commerce. Spanish Official State Gazette (BOE-A-2002-13758), consolidated text, accessed October 2026.
- 50 Cart Abandonment Rate Statistics 2026. Baymard Institute, accessed October 2026 (data from US online shoppers).
- Press Release from the Journal of Marketing: Boosting Returns on E-Commerce Retargeting Campaigns. American Marketing Association, 2020, on the article by Jing Li, Xueming Luo, Xianghua Lu, and Takeshi Moriguchi in the Journal of Marketing, vol. 85, 2021.
- Manage limited inventory. Stripe Documentation, accessed October 2026.