Google has revealed several new apps and features for G Suite customers today, including the new Hangouts applications and Drive File Stream. Gmail has long been one of the company's most-used products, and now enterprise users are getting Add-ons for Gmail.
Gmail Add-ons are designed to integrate custom workflows into Gmail based on the context of a given email. Add-ons only need to be written once, and work across Gmail on the web, Android, and iOS. Once the feature goes live, Add-ons will be available from the G Suite marketplace.
Intuit, Salesforce, and ProsperWorks are already developing their own Gmail Add-ons, and interested developers can sign up for more information. Personally, I hope some variation of this feature makes it to regular Gmail at some point.