> For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt.

# `build-env`

This option specifies environment variables to set when building on Vercel.

::: tip
If [prebuilt](/references/inputs/optional/prebuilt.md) is enabled, set environment variables when `vercel build` runs.
:::

## Usage example

```yaml {31-33} file="/snippets/references/inputs/build-env.yml"
name: Vercel

on:
  push:
    branches: [main]
  pull_request:

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  deploy:
    name: Deploy
    runs-on: ubuntu-latest
    permissions:
      contents: read
      deployments: write
      statuses: write
      pull-requests: write

    steps:
      - uses: actions/checkout@v7

      - uses: nexterias/actions-vercel@v2
        with:
          token: ${{ secrets.VERCEL_TOKEN }}
          org-id: ${{ secrets.VERCEL_ORG_ID }}
          project-id: ${{ secrets.VERCEL_PROJECT_ID }}
          production: ${{ github.ref == 'refs/heads/main' }}
          build-env: |
            FOO=BAR
            BAZ=QUX

```