Azure Kubernetes Engine

vs

Google App Engine

Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications.. It groups containers that make up an application into logical units for easy management and discovery. Kubernetes builds upon 15 years of experience of running production workloads at Google, combined with best-of-breed ideas and practices from the community.

K3s is a lightweight Kubernetes distribution by Rancher Labs intended for IoT, Edge, and cloud deployments.

With DigitalOcean App Platform you can build, deploy, and scale apps quickly using a simple, fully managed solution. Deploy code by simply pointing to a GitHub repo and let App Platform do the heavy lifting of managing the infrastructure, app runtimes and dependencies. 

Heroku is a platform as a service (PaaS) built especially for applications developers. When Heroku first launched in 2007 it was a platform dedicated to deploy and host Ruby applications. Today the offering has broadened and allows developers to launch applications for most languages, frameworks and technologies in a matter of minutes with the help of Heroku Buildpacks. There are currently over 5,400 Heroku Buildpacks in the Heroku Elements Marketplace, that can be used by developers to speed up deployment and saftley host their applications online.

Dokku is a free and open-source project that helps you build and manage the lifecycle of applications. With Dokku developers can setup their own PaaS (Platform-as-a-Service) in a matter of minutes. Dokku provides extra plugins which can be used to manage database, and tools needed for your application. If you need to server your application over HTTPS, Dokku got you covered as well, with the help of Let's Encrypts free TLS certificates.