# Empty slot alerts (/en/businesses/reservations/empty-slot-alerts) Every venue has time that goes unsold: a popular hour that is still free in the morning, or a booking cancelled too late for anyone to notice. Empty slot alerts offer that time to the customers most likely to book it, with a push notification in the Thril app. One push to every customer does not work. A free hour sells once, and the customers who missed it learn to ignore your messages. The alerts go to a small, ranked group at a time, and every customer gets one alert a day at most. Give each rule a customer list, because people ignore alerts that are not for them. Lists that work: - **Golf simulator regulars**, for evening simulator time nobody has booked. - **Students and seniors**, for the weekday daytime hours that are hardest to fill. - **Members who came last month but not this month**, to give them a reason to come back. You make the lists in [Customer lists](/businesses/marketing/customer-lists) and pick one on each rule. --- ## Turning it on [#turning-it-on] Under **Settings** → **Empty slot alerts**, save your first rule and switch on **Send empty slot alerts**. Switching it off pauses every rule at the venue. --- ## Rules [#rules] Make one rule per sport, such as one for your padel courts and one for your golf simulators. A rule offers two kinds of free time: - **Unsold time.** Time nobody has booked today. Each customer gets one message with your venue's name and the first free time, however many resources are free. - **Last-minute cancellations.** When a booking that starts soon is cancelled or put up for sale, the time goes back on offer at once. Switch off **Unsold time** if customers might learn to wait for free time. A last-minute cancellation looks like luck instead. Each rule also sets the sports and resources it covers, the customer list it goes to, and the hours unsold time comes from. Empty sports, resources or list cover the whole venue or all your customers. Thril handles the send times and how often a customer hears from you. --- ## How the alerts go out [#how-the-alerts-go-out] **Unsold time** goes out a few times a day, also at weekends, timed around when people book for the same day. People plan tonight's game over lunch. An alert offers time that leaves the group room to get together, and the more resources are free, the more customers it reaches. **A last-minute cancellation** goes out at once, whatever the time of day, because the time can start within the hour. The alert stops as soon as someone books. Thril ranks the customers on the rule's list by when they usually book, the sport they play and how recently they visited. A customer who plays on weekday afternoons hears about the afternoon time, and the same names don't get every alert. An alert skips customers who have turned alerts off, already have a booking at that time, or have had an alert today from any venue on Thril. **One alert a day from all of Thril** keeps a customer who follows five venues from hearing from all five at once. --- ## Hours to offer [#hours-to-offer] **From** and **Until** set the hours that unsold time comes from. The default covers the evening hours most venues charge most for. The range can run past midnight for a venue that closes late. --- ## Subscribing [#subscribing] With **Let customers subscribe** on, customers in your customer register can turn the alerts on from your venue page in the Thril app. Subscribers get alerts on top of each rule's customer list. --- ## Customer controls [#customer-controls] A customer can turn off alerts from your venue on your venue page in the Thril app, or from all venues in the app's notification settings. Alerts are push notifications that expire when the offered time starts. --- ## Sales from alerts [#sales-from-alerts] **Settings** → **Empty slot alerts** shows how many times the alerts sold, the sales after discounts, how many customers got alerts and how many of them booked, and what share of the offered times sold. Each rule shows what it sold. A booking counts when anyone on it got the alert and booked the offered time, also when a player asked a friend to make the booking.