About Backend Extensions
Backend extensions enable apps to customize Wix's backend business logic and add value to site builders and apps.
Service plugin extensions (formerly SPIs)
Service plugins are APIs that are defined by Wix, which you can choose to implement. When you implement a Wix service plugin in your app, you become a service provider. Wix then calls your service during one or more specified flows, waits for your response, and then continues the flow based on your response.
For example, a Local Delivery Provider app may implement the Restaurants Local Delivery service plugin, which includes a Get Delivery Estimate endpoint. Wix then calls this provider when they need to fetch applicable delivery estimates during a customer’s checkout flow.
Schema plugin extensions
Schema plugins are field extensions to Wix’s objects that you can use to enrich and extend Wix’s data. Every Wix API has a service object with predefined fields, that can’t be removed or changed. But sometimes there is a business need to include additional data that Wix doesn’t save by default.
For example, an app managing bookings and equipment rental for outdoor adventure companies may want to include equipment rental data as part of the booking. With a schema plugin, the app can add an equipment field to the Bookings Service object. The equipment field becomes a part of the object, and the app can retrieve and manage it with the Bookings APIs.
Notifications
Notifications allow you to send predefined messages with customizable data to your app's users in their site dashboard and/or the Wix Owner mobile app. This can be a useful way to alert users about important updates and events.
For example, an app managing a business’ social media presence may want to notify site builders about new media posts they are referenced in, likes, and so on.
Automations
Automations allow you to predefine functionality of multiple types, based on triggers and actions. Automations leave site owners free to focus on their business, instead of having to deal with the details of running their site.
For example, an app managing a business' community building tasks might automate a welcome email to everyone who signs up for the site's newsletter or purchases a product.