Inertia Rails

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Server-Side Rendering (SSR) ​

Server-side rendering pre-renders your JavaScript pages on the server, allowing your visitors to receive fully rendered HTML when they visit your application. Since fully rendered HTML is served by your application, it's also easier for search engines to index your site.

Server-side rendering uses Node.js to render your pages in a background process; therefore, Node must be available on your server for server-side rendering to function properly. Inertia's SSR server requires Node.js 22 or higher.

Vite Plugin Setup ​

Available since:inertia_rails:3.19.0@inertiajs/core:3.0.0

The recommended way to configure SSR is with the @inertiajs/vite plugin. This approach handles SSR configuration automatically, including development mode SSR without a separate Node.js server.

1. Install the Vite plugin ​

bash
npm install @inertiajs/vite

2. Configure Vite ​

Add the Inertia plugin to your vite.config.js file. And configure entry point.

js
// vite.config.js
import inertia from '@inertiajs/vite'

export default defineConfig({
  plugins: [
    // ...
    inertia({
      ssr: {
        entry: 'entrypoints/inertia.js',
      },
    }),
  ],
})

You may also configure SSR options explicitly.

js
// vite.config.js
inertia({
  ssr: {
    entry: 'ssr/ssr.js',
    port: 13714,
    cluster: true,
  },
})

You may pass false to opt out of the plugin's automatic SSR handling, for example if you prefer to configure SSR manually but still want to use the other features of the Vite plugin.

js
// vite.config.js
inertia({
  ssr: false,
})

3. Update your build script ​

Update the build script in your package.json to build both bundles.

json
{
  "scripts": {
      "dev": "vite",
     "build": "vite build"
     "build": "vite build && vite build --ssr"
  }
}

Development Mode ​

The Vite plugin handles SSR automatically during development. There is no need to build your SSR bundle or start a separate Node.js server. Simply run your dev servers as usual:

bash
bin/dev

The Vite plugin exposes a server endpoint that Rails uses for rendering, complete with HMR support.

NOTE

The vite build --ssr, bin/vite ssr, etc. commands are for production only. You should not run them during development.

Production ​

For production, build both bundles and start the SSR server.

bash
npm run build
node public/assets-ssr/inertia.js

Custom SSR Entry Point ​

The Vite plugin reuses your inertia.js entry point for both browser and SSR rendering by default, so no separate file is needed. The plugin detects the data-server-rendered attribute to decide whether to hydrate or mount, and the setup and resolve callbacks are optional.

Most app customizations, such as registering plugins or wrapping with providers, may be handled using the withApp callback in your main entry point. A separate SSR entry point is only needed when you require completely different setup logic for the server.

You may create a separate resources/js/ssr.js file for this purpose.

js
import createServer from '@inertiajs/vue3/server'

createServer((page) =>
  createInertiaApp({
    page,
    render: renderToString,
    resolve: (name) => {
      const pages = import.meta.glob('../pages/**/*.vue')
      return pages[`../pages/${name}.vue`]()
    },
    setup({ App, props, plugin }) {
      return createSSRApp({
        render: () => h(App, props),
      }).use(plugin)
    },
  }),
)

Be sure to add anything that's missing from your inertia.js file that makes sense to run in SSR mode, such as plugins or custom mixins.

Manual Setup ​

If you prefer not to use the Vite plugin, you may configure SSR manually.

1. Create an SSR entry point ​

Create an SSR entry point file within your Laravel project.

bash
touch app/frontend/ssr/ssr.js

This file will look similar to your app entry point, but it runs in Node.js instead of the browser. Here's a complete example.

js
import createServer from '@inertiajs/vue3/server'

createServer((page) =>
  createInertiaApp({
    page,
    render: renderToString,
    resolve: (name) => {
      const pages = import.meta.glob('../pges/**/*.vue')
      return pages[`../pages/${name}.vue`]()
    },
    setup({ App, props, plugin }) {
      return createSSRApp({
        render: () => h(App, props),
      }).use(plugin)
    },
  }),
)

2. Configure Vite ​

Next, we need to update our Vite configuration to build our new ssr.js file. We can do this by adding a ssrBuildEnabled property to Ruby Vite plugin configuration in the config/vite.json file.

json
"production": {
  "ssrBuildEnabled": true
}

3. Enable SSR in the Inertia's Rails adapter ​

Update Inertia Rails adapter cinfig to turn SSR on.

ruby
# config/initializers/inertia_rails.rb
InertiaRails.configure do |config|
  config.ssr_enabled = ViteRuby.config.ssr_build_enabled
end

Clustering ​

By default, the SSR server runs on a single thread. You may enable clustering to start multiple Node servers on the same port, with requests handled by each thread in a round-robin fashion.

js
// vite.config.js
inertia({
  ssr: {
    cluster: true,
  },
})

When using a custom SSR entry point or manual setup, you may pass the cluster option to createServer instead.

Available since:@inertiajs/core:2.0.7
js
createServer(
  (page) =>
    createInertiaApp({
      // ...
    }),
  { cluster: true },
)

Running the SSR Server ​

NOTE

The SSR server is only required in production. During development, the Vite plugin handles SSR automatically.

Puma Plugin ​

Available since:inertia_rails:3.20.0

The recommended way to run the SSR server in production is with the built-in Puma plugin. Add the plugin to your Puma configuration:

ruby
# config/puma.rb
plugin :inertia_ssr

The plugin automatically starts and stops the SSR Node.js process alongside Puma. It handles health checks, automatic restarts on crashes, and graceful shutdown. No separate process management (systemd, Procfile, etc.) is needed.

The plugin is a no-op when ssr_enabled is false or the SSR bundle is not found, so it is safe to add unconditionally.

Bundle Resolution ​

The plugin locates the SSR bundle using the following rules, in order:

  1. Explicit config — config.ssr_bundle (a path or an array of paths; the first existing file wins).
  2. ViteRuby output — if ViteRuby is loaded, it globs <ssr_output_dir>/*.js.
  3. ssr/ directory — globs ssr/*.js in the project root (matches the @inertiajs/vite plugin's default SSR build output).
  4. Legacy fallback — checks public/assets-ssr/*.js.

If none of the above finds a file, the plugin logs nothing and stays idle.

Runtime Detection ​

The JavaScript runtime is auto-detected from your lockfile (bun.lockb → Bun, deno.lock → Deno, otherwise Node.js). To override:

ruby
# config/initializers/inertia_rails.rb
InertiaRails.configure do |config|
  config.ssr_runtime = "bun"
end

Manual ​

If you are not using Puma, or prefer to manage the SSR process yourself, start the SSR server manually:

bash
bin/vite ssr

With the server running, you should be able to access your app within the browser with server-side rendering enabled. In fact, you should be able to disable JavaScript entirely and still navigate around your application.

Client-Side Hydration ​

You should also update your inertia.js file to use hydration instead of normal rendering. This allows Vue to pick up the server-rendered HTML and make it interactive without re-rendering it.

js
import { createApp, h } from 'vue'
import { createSSRApp, h } from 'vue'

createInertiaApp({
  resolve: (name) => {
    const pages = import.meta.glob('../pages/**/*.vue')
    return pages[`../pages/${name}.vue`]()
  },
  setup({ el, App, props, plugin }) {
    createApp({ render: () => h(App, props) }) 
    createSSRApp({ render: () => h(App, props) }) 
      .use(plugin)
      .mount(el)
  },
})

Error Handling ​

When SSR rendering fails, Inertia gracefully falls back to client-side rendering. The Vite plugin logs detailed error information to the console, including the component name, request URL, source location, and a tailored hint to help you resolve the issue.

Common SSR errors are automatically classified. Browser API errors (such as referencing window or document in server-rendered code) include guidance on moving the code to a lifecycle hook. Component resolution errors suggest checking file paths and casing.

The Rails adapter automatically logs SSR failures to Rails.logger at the error level. To customize error handling, set the on_ssr_error option in your config/initializers/inertia_rails.rb file.

ruby
# config/initializers/inertia_rails.rb
InertiaRails.configure do |config|
  config.on_ssr_error = ->(error, page) do
    Rails.logger.warn("SSR failed for #{page[:component]}: #{error.message}")
    Sentry.capture_exception(error) # or any error tracker
  end
end

The callback receives an InertiaRails::SSRError and the page hash, giving you access to the component name, props, and URL that failed.

Raising on Error ​

For CI or E2E testing, you may prefer SSR failures to raise an exception instead of falling back silently. Set the ssr_raise_on_error option in your initializer.

ruby
# config/initializers/inertia_rails.rb
InertiaRails.configure do |config|
  config.ssr_raise_on_error = true
end

SSR Response Caching ​

Available since:inertia_rails:3.19.0

SSR rendering sends a request to the Node.js server for every page load. You can cache these responses to avoid redundant renders when the same page data is served repeatedly.

Enabling SSR Caching ​

Set ssr_cache in your initializer:

ruby
# config/initializers/inertia_rails.rb
InertiaRails.configure do |config|
  config.ssr_cache = true
end

When enabled, the SSR response is cached using an MD5 digest of the page JSON as the cache key. Identical page data produces the same key, so the Node.js server is only called once per unique page.

Cache Options ​

Pass a hash to control cache behavior:

ruby
InertiaRails.configure do |config|
  config.ssr_cache = { expires_in: 1.hour }
end

Dynamic Configuration ​

Use a lambda for per-request control. The lambda is evaluated in the controller context:

ruby
InertiaRails.configure do |config|
  config.ssr_cache = -> { { expires_in: action_name == 'index' ? 1.hour : 5.minutes } }
end

Per-Render Override ​

Override the global setting on individual render calls:

ruby
class PostsController < ApplicationController
  def show
    render inertia: 'Posts/Show',
      props: { post: @post.as_json },
      ssr_cache: false  # skip caching for this render
  end
end

Development Mode ​

SSR caching is automatically disabled when the Vite dev server is running, since dev responses change frequently and should not be cached.

Cache Store ​

SSR caching uses the same cache_store as cached props. SSR cache keys are prefixed with inertia_ssr/.

Disabling SSR ​

Sometimes you may wish to disable server-side rendering for certain controllers or pages in your application. You may do so by setting the ssr_enabled option to false using inertia_config.

ruby
class AdminController < ApplicationController
  inertia_config(ssr_enabled: false)
end

You can also use a lambda for conditional SSR, which is evaluated per-request in the controller context:

ruby
class DashboardController < ApplicationController
  inertia_config(ssr_enabled: -> { !complex_client_only_page? })
end

Deployment ​

When deploying your SSR enabled app to production, build both the client-side (application.js) and server-side bundles (ssr.js), and then run the SSR server as a background process — either via the Puma plugin or manually.

NOTE

The Puma plugin expects Node.js (or your configured runtime) to be available in the same environment as Puma. For containerized deployments where the SSR server runs in a separate container, skip the plugin and point ssr_url to the SSR container instead.