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Last Reviewed: 2026-07-06

Frontend Asset Builds

Learn how to compile frontend assets on Pantheon.

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Pantheon allows you to compile frontend assets (themes, design systems, and other Node.js-based tooling) automatically on the platform as a build step. This build step runs on every code push, so compiled assets no longer need to be committed to your site repository.

Compatibility & Requirements

  • Supported for both WordPress and Drupal sites, with or without Integrated Composer
  • Node Versions:
    • Frontend builds support Node.js 22, 24, and 26 (default)
  • Package manager:

    • Selected based on the lock file present in each configured build path. The platform checks for lock files in the following order and uses the first match:

      1. bun — bun.lock or bun.lockb
      2. pnpm — pnpm-lock.yaml
      3. yarn — yarn.lock
      4. npm — package-lock.json
      Note

      A lock file is required. If no lock file is found in a build path, the build fails. Commit the lock file for your chosen package manager to enable reproducible installs.

Usage

Add a frontend_build block to your pantheon.yml:

Each entry under paths describes one directory to build:

  • path — the directory containing the package.json and lock file, relative to your repository root.
  • node_version — the Node.js major version to build with. Defaults to 26.
  • build_command — the script to run (executed as <package-manager> run <build_command>). Defaults to build.

You can list multiple paths to build several themes or packages in a single deploy.

After configuring your site's pantheon.yml file as described above, you must also update your .gitignore file so that you ignore all the artifacts that the build process will produce.