ness start

Serves an existing production build using the Ness Node runtime.

ness start [options]

Option	Description	Default
--host <host>	Server hostname	0.0.0.0
--port <port>	Server port	3000
--build <file>	Server build entry	build/server/index.js

ness build
ness start --host 127.0.0.1 --port 8080

When flags are omitted, HOST and PORT environment variables override the listed defaults, which makes the command work with managed hosting platforms without wrapper scripts.

The production runtime serves immutable assets, public files, SSR and RSC responses, routing rules, middleware, page caching, image optimization, and the Ness health endpoint at /_ness/health. The command fails early when the selected server build does not exist.

Responses are compressed per request after negotiating Accept-Encoding — Brotli first, then gzip — and a precompressed .br or .gz twin sitting next to an asset is served instead of being compressed again, with the original Content-Type kept and Vary: Accept-Encoding set. server.compression: false in ness.config.mjs turns both off.

With server.trustProxy enabled, X-Forwarded-Proto and X-Forwarded-Host are applied to the request URL before the request is handled, so redirects and generated links use the address the visitor reached. It is off by default, because those headers come from the client unless a proxy overwrites them.

On SIGINT or SIGTERM the server drains: /_ness/health starts answering 503 while in-flight requests finish, and idle connections are closed as they free up. The grace period is server.shutdownTimeout — 10 seconds by default, and NESS_SHUTDOWN_TIMEOUT overrides it — after which the remaining connections are cut and the process exits 1.

The server section comes from ness.config.mjs when the project has one, and from ness.server.config.mjs otherwise — the runtime-only file the Worker and Lambda targets read. Whichever file is found, the same resolution runs on every target, so ness start and a deployed build honour the same settings.