Vercel Deploy

Vercel Deploy

Ship a Next.js app to Vercel and control its environments safely: preview deploys for review, production promotes behind confirmation, and a fast rollback when a deploy goes bad. Deploying is publishing — every production action is gated.

Contract

Inputs:

• A linked Vercel project; mode preview (default), prod, rollback, or env.

Outputs:

• A deployment URL (preview or production), or the restored deployment (rollback), or the env-var change summary.

Creates/Modifies:

• Vercel deployments and environment variables. Production deploys, promotions, env changes, and rollbacks happen only after confirmation.

External Side Effects:

• Publishes to Vercel. A production deploy is user-visible immediately. No git writes.

Confirmation Required:

• Before any production deploy or promotion.
• Before changing or removing an environment variable.
• Before a rollback (name the target deployment first).

Delegates To:

• monitoring-setup to confirm error tracking is live before a production deploy.
• dependency-audit / security-audit as a pre-production gate on risky releases.

Step 0 — Verify the project is linked (safety gate)

Never deploy an unlinked project, and never link one unattended:

test -f .vercel/project.json || { echo "Not linked — .vercel/project.json missing."; exit 1; }
vercel whoami    # confirm the CLI is authenticated as the right account

If .vercel/project.json is absent, stop and ask the user to run vercel link themselves — do not run it for them. Linking to the wrong project deploys to the wrong place.

Step 1 — Preview deploy (default)

A preview build for review — never production:

vercel                 # builds and deploys a preview; prints the preview URL

Report the preview URL. This is the safe default for any "deploy this" without an explicit production ask.

Step 2 — Production deploy (prod)

Confirm first, then promote. Prefer promoting an already-built preview over a fresh --prod build so what ships is what was reviewed:

vercel --prod          # builds and deploys straight to production
# or promote a specific, already-reviewed deployment:
vercel promote <deployment-url>

Before running: state what will go live (branch/commit), confirm error tracking is on (monitoring-setup), and get an explicit yes. Production is live to users the moment this returns.

Step 3 — Rollback (rollback)

When a production deploy is bad, roll back to the last known-good deployment:

vercel ls --prod                     # list recent production deployments
vercel rollback <good-deployment-url>   # or `vercel promote` the known-good one

Name the target deployment (URL + commit) and confirm before rolling back. Rollback is itself a production change.

Step 4 — Environment variables (env)

Manage vars per environment; production changes are gated:

vercel env ls                                  # what's set, per environment
vercel env add <NAME> production               # prompts for the value (not echoed)
vercel env rm <NAME> production                # after confirmation

Never print a secret value into the transcript. Set the same var across development, preview, and production deliberately — a var present in preview but missing in production is a classic "works in preview, 500s in prod" bug.

Anti-Patterns

• Deploying an unlinked project or running vercel link unattended — stop and ask; linking to the wrong project ships to the wrong place.
• vercel --prod without confirmation — production is live immediately; preview is the default.
• Fresh --prod build instead of promoting the reviewed preview — promote what was reviewed so prod matches what was tested.
• Echoing secret env values into the transcript.
• A rollback without naming the target — confirm the exact known-good deployment first.