Gitpod co-founder here.

Gitpod = server-side-dev-envs + dev-env-as-code + prebuilds + IDE + collaboration.

1. From a Git Repository on GitHub, Gitlab or Bitbucket, Gitpod can spin up a server-side-dev-environment for you in seconds. That's a docker container that you can fully customize and that includes your source code, git-Terminal, VS Code extensions, your IDE (Theia IDE), etc. The dev environment is enough powerful to run your app and even side-services like databases.
2. Step (1) is easily repeatable and reproducible because it's automated and version-controlled and shared across the team. We call this dev-environment-as-code. Think of infrastructure-as-code for your dev environment.
3. After (1), you're immediately ready-to-code, because your workplace is already compiled and all dependencies of your code have been downloaded. Gitpod does that by running your build tools on git-push (like CI/CD would do) and "prebuilds" and store your workspace until you need it. This really shines when reviewing PRs in Gitpod.
4. Collaboration becomes much easier once your dev environments live server-side and your IDE runs in the browser. Sending a snapshot of your dev environment to a colleague is as easy as sending a URL. The same goes for live shared coding in the same IDE and dev-environments.

At the end of the day, you start treating your dev environments as something ephemeral: You start them, you code, your push your code, and you forget your dev environment. For your next thing, you'll use a fresh dev environment.

The ease of mind that you get from not messing, massaging, and maintaining dev environments on your local machine is incredibly liberating.

Gitpod can be used on gitpod.io, or self-hosted on Kubernetes, GCP, or AWS.