Build environment

Builds run in a Linux container, one per build, destroyed when the build ends.

System and tools

Corepack honors the packageManager field of your package.json, so a pinned pnpm or Yarn version is the one used.

Network access

A build can only reach:

• registry.npmjs.org and registry.yarnpkg.com;
• github.com, codeload.github.com and objects.githubusercontent.com;
• nodejs.org.

Anything else fails to connect. In practice:

• Private registries (a company npm mirror, GitHub Packages) aren't reachable yet.
• A build step that calls an API (fetching content from a CMS at build time, uploading source maps) fails. Do it at runtime, or before deploying.
• Dependencies that download a binary on install from another host fail. Most publish their binaries to npm, which works.

Resources

CPU, memory and disk are your build machine's. A build that runs out of memory is stopped, usually with a Killed or JavaScript heap out of memory line: pick a bigger machine.

Each build has a time limit, set by your plan:

Environment variables

None of your project's environment variables are set during the build: they reach your app at runtime. A value the build itself needs can go in the build command; see Vite.