Heroku is a platform as a service (PaaS) that allows developers to build, run, and operate applications entirely in the cloud. As a Salesforce company, it supports popular languages like Ruby and Node.js, offering data services like Postgres and Redis, and a vast ecosystem of over 180 cloud app services. Heroku powers over 5 million apps, including those from companies like Live Nation Entertainment, HealthSherpa, and Airbase, providing a faster, more efficient way for businesses to create, deploy, and manage applications.