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Astro

Fly.Website.Astro deploys an Astro project to Fly as a Node server on a Machine. Server-rendered pages run on a Fly.Service (port 3000); static files are served first, then the Astro handler. Omit app and Alchemy creates a Fly.App plus a shared IPv4 so https://{app}.fly.dev answers. Your astro.config.* loads natively — don’t declare an adapter.

Install

Section titled “Install”

The build integration is not bundled with alchemy. Install @alchemy.run/frontend-frameworks; the resource loads its /astro and /astro/node exports from your project at deploy time. It is only used at build time, so a dev dependency is enough:

Terminal window
bun add -d @alchemy.run/frontend-frameworks

Configure Astro

Section titled “Configure Astro”

Your astro.config.* file loads natively — integrations, Vite plugins, and any other non-serializable options work exactly as they do outside Alchemy. Alchemy merges a programmatic config over it: the Node adapter is injected for you (don’t declare an adapter in your config — that fails the build with an actionable error), and options passed via the astro prop override the file’s — see Astro configuration below for the details.

Declare the Website

Section titled “Declare the Website”

Declare the site as a module-level const (rather than inline in the Stack):

alchemy.run.ts
import * as Fly from "alchemy/Fly";


export const Website = Fly.Website.Astro("Website");

Pass rootDir if package.json is not at .. Pass app to put the Service on an App you already declared; otherwise the site creates Fly.App("App") under its namespace.

Add it to the Stack

Section titled “Add it to the Stack”

Yield the site from your Stack and return its URL:

alchemy.run.ts
import * as Alchemy from "alchemy";
import * as Effect from "effect/Effect";


export default Alchemy.Stack(
  "MyAstroSite",
  {
    providers: Fly.providers(),
    state: Alchemy.localState(),
  },
  Effect.gen(function* () {
    const site = yield* Website;
    return { url: site.url };
  }),
);

Pages are server-rendered by default. Pages that export const prerender = true are prerendered at build time and served as static files.

On deploy the site is one App, one Service on port 3000, and a shared IPv4. site.url is https://{app}.fly.dev (or https://{domain} when you set domain). site.app, site.service, site.ip, and site.certificate are undefined under alchemy dev.

Add environment variables

Section titled “Add environment variables”

Process environment is the top-level env prop — plain strings, or Redacted values. They are copied onto process.env before build and alchemy dev, and onto the Machine at deploy:

alchemy.run.ts
export const Website = Fly.Website.Astro("Website", {
  env: {
    GREETING: "Hello from Alchemy!",
    API_BASE: "https://api.example.com",
  },
});

This is the hosted Node process, not Worker bindings.

Read the environment in server code

Section titled “Read the environment in server code”

The Astro server runs in Node on the Machine, so server-rendered pages and endpoints read the environment from process.env:

src/pages/index.astro
---
const greeting = process.env.GREETING ?? "hello";
---


<h1>{greeting}</h1>

Astro inlines PUBLIC_* keys at build time. Because env is applied before the build, those keys behave the same as in a local astro build.

Fully static sites

Section titled “Fully static sites”

With astro: { output: "static" } every page is prerendered at build time and the deploy is assets-only — no Astro handler, just a static-file server on the Machine:

export const Website = Fly.Website.Astro("Website", {
  astro: { output: "static" },
  assets: { notFoundHandling: "404-page" },
});

assets.notFoundHandling applies only to output: "static". "404-page" serves the built 404.html for unmatched routes; "single-page-application" answers misses with the index page (200) instead.

Astro configuration

Section titled “Astro configuration”

Your astro.config.* is the primary place to configure Astro — integrations, Vite plugins, and every other option (serializable or not) work as usual:

astro.config.ts
import { defineConfig } from "astro/config";
import react from "@astrojs/react";
import tailwindcss from "@tailwindcss/vite";


export default defineConfig({
  site: "https://blog.example.com",
  integrations: [react()],
  vite: {
    plugins: [tailwindcss()],
  },
});

The astro prop on the resource exposes common serializable options for deploy-specific overrides; Astro merges them over the config file (scalars override, arrays like integrations and vite.plugins concatenate after the file’s):

alchemy.run.ts
export const Website = Fly.Website.Astro("Website", {
  astro: {
    site: "https://preview.example.com",
  },
});

Two options are managed for you regardless of the config file:

  • adapter — Alchemy injects the Node adapter. Declaring an adapter in astro.config.* fails the build with an actionable error.
  • output — Alchemy defaults it to "server" (superseding a file-level output), so pages render on demand on the Machine. Opt into a fully prerendered site with astro: { output: "static" } on the resource.

site, base, srcDir, publicDir, outDir, and trailingSlash are the other serializable keys on astro.

Local dev

Section titled “Local dev”

alchemy dev runs Astro’s own dev server (native HMR) instead of deploying; site.url is the local address and no Fly resources are created. Wrap the site in Alchemy.remote() to deploy the real App and Service even during dev.

Custom domain

Section titled “Custom domain”

domain is a hostname string. The site requests an ACME Fly.Certificate on the App and url becomes https://{domain}. Point DNS at the App yourself — v1 does not create DNS records:

export const Website = Fly.Website.Astro("Website", {
  domain: "app.example.com",
});

Where next

Section titled “Where next”