Dev Servers

A Vite, Next.js, Nuxt, or Astro project isn't a folder of files a web server can hand out. It only works while its own dev server runs. Rezure handles that for you: Nginx passes every request for the project's .test domain to the dev server's port, and Rezure starts the dev server when you open the project.

So http://my-astro-site.test works the same way http://my-laravel-app.test does, with hot reload included, and you don't need to remember localhost:5173.

New in Rezure 3.3.

Which projects use a dev server

Every project detected as Vue, React, Svelte, Angular, Astro, Next.js, Nuxt, or Node. That includes Node apps that listen on a port of their own, such as an Express API or a self-hosted tool. See Frameworks for how detection works.

To serve a JavaScript project's built output (dist/) as plain files instead, open its framework badge and pick Custom folder…. To put a project on a dev server that detection missed, pick its framework from the same badge.

Laravel with Vite is different: the site is still served by PHP, and Laravel's Vite plugin talks to npm run dev directly. See Node.js.

Open a project

Click Open on the project's row. If the dev server isn't running, Rezure:

1. Shows that it is starting the dev server.
2. Runs the project's script (npm run dev, for example) on the project's port.
3. Waits until the port answers, and only then opens your browser, so you land on the app and not on an error page.

The small dot on the Open button shows its state: grey when stopped, pulsing while it starts, and green while it runs.

If it fails to start, the browser isn't opened. A message under the header says why, with Fix in Dev servers, which opens the dialog at that project.

With Open starts it turned off, Open only opens the browser. Until you start the server, the page reads "This project's dev server isn't running".

The Dev servers dialog

Dev servers, next to Sync hosts file on the Projects page, lists every project served this way. Its badge counts the ones running.

Each project's card shows its domain, framework, status (Running, Starting…, Stopped), the exact command it runs, and Start / Stop / Log. Stop all stops every dev server at once.

Setting	What it does
Port	Where Nginx sends the domain. Rezure picks one from 4400–4499 the first time and keeps it, so a domain always reaches the same port. Change it for an app that listens on a fixed port of its own.
Tell it the port with	How the dev server is told to use that port. The default comes from the framework. See below.
Script	The package.json script that starts it. The dropdown lists the project's scripts.
Open starts it	On: Open starts the dev server first. Off: you start it yourself.

Port and script can only be changed while the dev server is stopped ("Stop it to change its port or script."). Click Save to keep a change, or Revert to drop it.

Settings are kept in C:\rezure\etc\dev-servers.json. Don't edit that file while Rezure runs.

How the port is passed

Option	Added to the command	For
--port + --strictPort	-- --port 4400 --strictPort	Vite (Vue, React, Svelte). Without --strictPort, Vite quietly moves to the next port when its own is taken.
--port	-- --port 4400	Next.js, Nuxt, Astro, ng serve
PORT variable only	nothing	Create React App, and Node apps that read process.env.PORT
The app's own port	nothing	Apps that always use the same port. Enter that port in Port.

The PORT environment variable is set in every case.

Default scripts

Framework	Script
Vue, React, Svelte, Astro, Next.js, Nuxt	dev
Angular, Node	start

If package.json doesn't have the default, Rezure tries dev, then start. If neither exists, the card says so and lets you pick one.

Port rules

When you save a port, Rezure checks it before keeping it:

• It must be between 1024 and 65535.
• No other project may use it.
• It can't be one of Rezure's own ports: 80, MariaDB/MySQL, PostgreSQL, the PHP ports, Mailpit, or the LocalDB bridge. See Ports.

When a dev server can't start yet

The card tells you what's missing and offers the fix:

Message	Fix
"Its dependencies aren't installed yet."	Click npm install (or pnpm install, yarn install, bun install, depending on the project's lockfile). Its output shows in the card's log.
"Node.js isn't installed." / "Set to Node.js x, which isn't installed."	Open Switch and install it. See Node.js.
"package.json has no "dev" script"	Pick the right script from Script.
"This project uses pnpm, which isn't installed."	Run corepack enable in a terminal, or install pnpm (or yarn).
"It's already running outside Rezure …"	Click Stop it and start here. See below.
The port is held by another program	Click Free port N and start, the same flow as Port Conflicts.

Already running in a terminal

If you started the same dev server yourself, with npm run dev in a terminal or an IDE's run button, Rezure finds it. It looks for a Node, Bun, or Deno process working in the project's folder and listening on a port. Astro and Next.js refuse to run twice in one folder, and two copies would fight over ports anyway.

Stop it and start here stops that copy's server and starts Rezure's own on the project's port. The terminal you typed the command in stays open. A build watcher or test runner in the same folder is left alone, because it doesn't listen on a port.

Clear error messages

When a dev server exits during startup, Rezure keeps its last 40 lines of output and shows the actual error rather than the stack trace under it. For familiar failures it adds the fix: another copy already running, a lock file, EADDRINUSE, or a missing module (→ Install). Log shows the full output.

What Rezure does and doesn't do

• Dev servers start only when you ask, with Open or Start. They aren't on the Services page and Start all never starts them, since each can take hundreds of MB of memory.
• Each runs on the project's own Node.js version when the project pins one.
• Every dev server stops when Rezure closes. One left over from a crash is cleaned up the next time that dev server starts.
• A dev server that exits on its own isn't restarted, because a compile error would only crash it again. Its log says what happened.
• Sharing works as for any project: the Cloudflare tunnel goes through Nginx to the dev server.
• Dev servers are never included in Rezure's usage data.

Hot reload, Vite, and Next.js

Nginx passes websockets on, so hot module replacement works through the .test domain. Rezure also handles the two host checks that usually break this kind of setup:

• Vite rejects requests for hostnames it doesn't know ("Blocked request. This host is not allowed"). Rezure tells Vite to accept the project's domain, so vite.config needs no allowedHosts entry.
• Next.js 16 rejects its own dev resources (/_next/*, including the hot-reload websocket) for any origin other than localhost, which leaves the page stuck on its loading screen. Rezure's virtual host drops the Origin header on those paths only when it's the project's own domain, so next.config needs no allowedDevOrigins. Requests from any other site are still refused.

Vite listens on localhost, which on many Windows machines means IPv6 (::1) only. Nginx tries 127.0.0.1 first and falls back to [::1], so both work.

Troubleshooting

"This project's dev server isn't running"

Nothing answers on the project's port. Click Open, or Start in Dev servers. If you start the server yourself, make it listen on the port Dev servers shows.

"Blocked request. This host is not allowed" from Vite

Your Vite version is too old to accept extra hosts from Rezure. Add this to vite.config:

export default {
  server: { allowedHosts: ['.test'] }
}

Hot reload doesn't update the page

Open the site through its .test domain after the dev server is up, and check the browser console for a failed websocket. A server.hmr setting in vite.config that names another host or port overrides what Nginx forwards.

"It's listening on :3001 instead of :4400"

The dev server ignored the port it was given. That's typical of a script that wraps it, such as concurrently or a custom server.js. Either set Port to the one it actually uses and Tell it the port with to The app's own port, or make the script pass --port on.

A Next.js page stays on its loading screen

Restart the dev server from Dev servers, then reload through the .test domain. Rezure 3.3 and newer handle Next 16's origin check (see above). If you added your own allowedDevOrigins for a workaround, you can remove it.

The project shows up as a PHP site instead

Detection didn't see a JavaScript framework. Maybe package.json is in a subfolder, or the framework is a dependency of a dependency. Click the framework badge and pick the right one.

Related

• Frameworks: how projects are detected, and changing it
• Node.js: install versions and pin one per project
• Projects: domains, the hosts file, and project actions
• Ports: every port Rezure uses