Heroku is an ecosystem of cloud services, which can be used to instantly extend applications with fully-managed services. Using an existing, high-quality service is something that empowers developers – they can build more, faster, by using trusted services that provide the functionality that they require.
Heroku Add-ons are fully-managed services, integrated for use with Heroku. They can be provisioned and scaled in one command, and let developers extend the capabilities of an application. Over 140 Add-ons are available, providing services ranging from databases to uptime alerts, messaging services or automatic backups to search, metrics or mail delivery.