astro-build-manifest

Static-first build manifest generation for Astro.

astro-build-manifest is a minimal Astro integration that outputs a deterministic build-manifest.json file at build time, describing exactly what pages and assets Astro generated.

It is designed for static sites first and never runs at runtime.

Why this plugin exists

After a build, teams often ask:

• What routes were actually generated?
• Did /about/ build correctly?
• What files did Astro emit?
• Why is a page missing in production?

Astro already knows this information internally, but does not expose it in a simple, machine-readable way.

astro-build-manifest exposes that data safely and honestly.

What it does (v1)

On astro build, the plugin writes a file to your output directory:

/build-manifest.json

Example output:

{
  "pages": [
    "/",
    "/about/"
  ],
  "assets": [
    "/index.html",
    "/about/index.html",
    "/_astro/main.abc123.css"
  ],
  "generatedAt": "2026-01-08T19:08:18.024Z"
}

What is included

Pages

• All routes Astro generated during the build
• Normalised with leading and trailing slashes
• / always represents the homepage

Assets

• Files emitted by Astro’s build pipeline
• HTML entrypoints
• CSS and JavaScript bundles
• Only public, web-facing paths

What is intentionally excluded

• Files in /public
• Environment variables
• Runtime state
• Absolute filesystem paths
• Server or adapter information

This keeps the manifest deterministic, portable, and safe to expose publicly.

Installation

npm install astro-build-manifest

Usage

Add the integration to your astro.config.mjs:

import { defineConfig } from "astro/config";
import astroBuildManifest from "astro-build-manifest";

export default defineConfig({
  integrations: [
    astroBuildManifest()
  ]
});

Then run:

astro build

Output guarantees

• Static-only
• Deterministic JSON
• Public-safe paths only
• No runtime execution

Versioning

• v1.x — static build manifest only
• v2 (planned) — optional public directory inclusion and diffing

License

MIT

Author

Built and maintained by Velohost
https://velohost.co.uk/

Project homepage:
https://velohost.co.uk/plugins/astro-build-manifest/