Production and deployment

Produce one immutable artifact

Install from the lockfile, typecheck source and tests, validate generated bindings, run browser tests, and build once. Promote the same artifact through environments. Rebuilding after approval changes the release.

Fingerprint immutable assets. Revalidate HTML and route manifests so they reference current fingerprints. Version service-worker caches and remove obsolete entries only after the new worker can serve a complete application.

Verify production behavior

Smoke-test generated output with development fallbacks disabled. Cover direct route entry, refresh on nested URLs, CSP, API credentials, loading and failure states, offline behavior, and service-worker upgrade from the previous release.

Design rollback before deployment

Retain the previous artifact. Determine whether storage migrations, server contracts, or service-worker caches make rollback incompatible. Prefer additive data changes.

Attach a release identifier to errors and operations. After deployment, verify asset integrity, critical routes, request latency, error rate, and one synthetic workflow. Stop promotion or roll back from explicit thresholds.

Follow the upgrade procedure for framework changes.