Create an app with Fly Launch

This guide goes into some detail about using Fly Launch to create and configure an app. See Getting Started for ways to get going even faster.

Fly Launch is a collection of opinionated Fly.io platform features that help you configure and orchestrate your app as a unit.

Create an app with Fly Launch

To create a brand new app on Fly.io, run this command from the source directory of your project:

fly launch

If you’re in a hurry, you can also try our super-simple demo app. Or get started with your favorite language or framework.

Ingredients for a successful fly launch

The components of a successful launch, ready for the first deployment:

Framework launch scanners

Depending on your project, fly launch may be able to look at your app’s source code and get through that ingredient list, straight to a ready-to-deploy Fly App. This is most likely to work for frameworks on which Fly.io has people specializing full time. Right now that’s Elixir/Phoenix, Laravel, Rails, and Django, but we also have launch guides for other languages and frameworks.

Our best scanners furnish a Dockerfile from which your app’s image will be built. Some of our terrible older scanners may invoke buildpacks, which tend to be slow and brittle.

Running fly launch in a directory containing a working Django app (it happens to be the one from our Django getting-started example):

fly launch

Scanning source code
Detected a Django app
Creating app in /flyio/hello-django
We're about to launch your Django app on Fly.io. Here's what you're getting:

Organization: MyName                 (fly launch defaults to the personal org)
Name:         hello-django           (derived from your directory name)
Region:       Amsterdam, Netherlands (this is the fastest region for you)
App Machines: shared-cpu-1x, 1GB RAM (most apps need about 1GB of RAM)
Postgres:     <none>                 (not requested)
Redis:        <none>                 (not requested)

? Do you want to tweak these settings before proceeding? Yes
...

The flyctl Django scanner has taken ownership of the launch. You can tweak the basic settings on the Fly Launch web page and then run fly deploy to deploy the new app. Visit our Django guide to see how that story will end. (Spoiler: it has a happy ending.)

Custom launch

You can nudge fly launch to better suit your project.

Point to an image or use a Dockerfile to build

Tell fly launch how you want to get the Docker image for your app, using either the --image or --dockerfile option, or by catching the Dockerfile launch scanner’s attention with the presence of a Dockerfile in your project source directory. The Dockerfile scanner doesn’t do a lot of configuration, but it prevents other scanners from taking over.

The actual Docker image build (or image pull) for a Fly App takes place during deployment. fly launch sets the stage by recording how to build, or get, the image, and both the first and all later deploys use that information.

Customize the configuration file

You can provide your own fly.toml and fly launch will offer to copy that configuration to a new app. fly.toml sets a starting point for the app configuration, and in some cases a framework launch scanner might overwrite parts of it.

The fly launch command has plenty of options you can use to control how your app gets created and provisioned.

If fly launch doesn’t have a scanner that can set up your app automatically, it will still initialize a new Fly App in your Fly.io organization and provide you with a default app configuration that’s a reasonable starting point for a simple web app.

You’ll need to ensure that your Fly App’s name is unique across all of Fly.io. By default, Fly Launch will derive an app name from the current directory name. If this is something common like “hello-world”, then there’s a good chance your launch will fail. You can use the --name flag to specify a unique name up front.

You can also perform an entirely manual “launch”, skipping all the launch scanners and full-service resource provisioning, using fly apps create, a hand-crafted (or copied) fly.toml, and step-by-step resource provisioning, followed by fly deploy.

After fly launch

If you’ve run fly launch but haven’t deployed yet (hint: you can do this with fly launch --no-deploy), or you deployed but want to make changes, then you can:

And then deploy (or redeploy) with fly deploy.

Grow and scale

Check out some of the ways you can increase availability, capacity, and performance with Fly.io:

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