Overview

Dev Servers are instant development and preview environments for your Git Repositories.

They are automatically kept in sync with your Git Repository, and use cache optimizations to maximize performance while minimizing cost.

Dev Servers are auto-healing; we automatically detect if a running dev server has crashed and restart it for you.

How to think about Dev Servers

Dev Servers are workbenches for AI to work on Git Repositories. Unlike Freestyle VMs, which are general purpose computers, Dev Servers themselves are built around the Git repo as the source of truth.

Whenever a Dev Server shuts down, we keep an image of the running VM around as a cache to make starting it again incredibly fast and cheap. However, if you don't use it we prioritize cost savings and automatically delete the cache for you regularly. This means data on the VM itself is not reliably persistent — which makes sense when the source of truth is the Git repo. For a more in depth look into how caching looks, see How the Cache Works.

Dev Server configuration lives on the Git repo itself. You can store environment variables, port configurations, dev commands and anything else relevant on the repository dev server configuration.

Dev Servers can be created for git repo branches. When a branch doesn't exist, we automatically create a new branch off of the main branch and sync a new dev server for it. These dev servers all share the same cache, so they are incredibly fast and cheap to start. This makes them perfect for AI to use as workbenches to try out ideas in isolation.

Where they fit

Dev Servers are not meant to be general purpose computers. If you need a general purpose computer, use Freestyle VMs. Freestyle Dev Servers is built on top of Freestyle VMs and take advantage of their unique capabilities like super-fast forking and ephemeral/cache modes.

Dev Servers are meant to be used as workbenches for AI to work on Git Repositories. They don't have persistence guarantees, so they are great when you want to store your source of truth somewhere else, like Git or some other external data store.

Extras

Dev Servers are automatically waking on request. This means if a dev server is stopped, and a request comes in to it, we automatically start it and handle the request. This makes them perfect for hosting preview environments for your branches. It also removes a whole set of common errors relating to servers not being there when they are expected. Even if there is no cache, we will automatically bring the dev server up from scratch to handle the requests, then shut it down when its no longer used.

Dev Servers support web previews on multiple ports. Instead of just 443 HTTPS, we've also opened up 8081 over HTTP. This allows you to run backends that require HTTP.

Dev Servers come with a web terminal interface, a web VSCode interface, both of these help whenever you need to debug, and work with autowaking.

Dev Servers come with a managed Git identity. This means your dev server can push and pull code from the repository it is associated with, without you needing to manage SSH keys or tokens. This makes it easy to have AI models that can work on code, and push changes back to the repo.

Dev Servers come with a MCP interface that your AI can use to work with them, this is also auto-waking so your AI can always connect to the dev server without worrying about if it is running or not.