“Build baby build” is our motto for this week as we have exciting announcements for building your projects on Railway.

The moment you’ve all been waiting for, Nixpacks will become the default builder for new projects starting 

. This coincides with the Nixpacks 0.2.0 release that adds significant improvements.

We never tire of explaining what NixPacks is, so here it is again if you don’t know. Nixpacks is our best answer to the question of reliable, reproducible builds. It works in two phases. The first phase analyzes the source directory and generates a build plan that includes a list of Nix packages, how to install the app, and build and start commands to run. It also pins the installable 

This means that the app source + build plan will always produce the same image. The second phase takes the source code and build plan and generates an OCI compliant image (using Docker) that can be deployed to Railway.

Part of having the fine grained control over the build process means we can focus on performance. Meaning: builds are very, very, fast with Nixpacks. The proof is in the pictures.

No action is required on your end and if you wish to enable it on your projects, you can select the option within the service settings.

By default, Nixpacks will cache directories during the install and build phases. The exact directories are determined based on the language and frameworks your app is using (e.g. if you are using Node then Nixpacks caches 

), and they are typically used by package managers or build tools to store downloads or build artifacts locally for fast reuse. This drastically speeds up your subsequent builds. Some rough numbers based on boilerplate apps

This one came from user feedback. Railway doesn’t kick off builds for PR deploys if a user was not part of your project. We also wouldn’t tell you that we didn’t. Users reported that the lack of notification around this process was confusing. We’ll admit that the lack of a heads up is confusing too.

Now, for projects that have PR deploys enabled, you’ll get a nifty comment suggesting that the user gets added to your project or team to make magic happen.

Railway was featured on Theo’s YouTube channel when highlighting Bun. Nixpacks got a nice shoutout! 

 had our founder Jake on to talk more about Railway and the founding story. Other topics discussed are future plans, what we have been working on, and the hosts favorite tools they’re seeing. 

Just like GhostBusters 2, we have a follow up to our fixes fighting phantom containers. Let us know if you run into any more issues

Shipped a feature that helped our logging service be more stable

Fixed minor issues within the UI related to banner spacing

Changed the oil on our Builder machine, builds should move to the deploy quicker.

https://res.cloudinary.com/railway/image/upload/v1657326491/docs/nix-default_xmqt0j.png

Nixpacks Cutover, Build Caching, Invite PR Comments 

Changelog #0089