# Preview tag contract

Use with [Temporary AWS preview environments that expire](/blog/automate-ephemeral-aws-preview-environments/). Checked 19 October 2026.

| Tag | Required value |
| --- | --- |
| Environment | `preview` |
| PullRequest | pull-request number |
| ExpiresAt | ISO-8601 date |
| Stack | `preview-pr-<number>` |

Cleanup may call destroy only when every ARN in the batch has `Environment=preview` and `Stack` starts with `preview-pr-`. One resource missing the tag aborts the batch.

## Stop

- Terraform workspaces as the way you separate production from staging. That warning is on the [command cheat sheet](/blog/terraform-commands-cheat-sheet-aws-2026/).
- A cleanup role that can `ec2:TerminateInstances` on `*`.
- The cost model for shared staging versus ephemeral. That comparison stays on the [CI/CD cost article](/blog/cost-aware-cicd-pipelines-aws/).