Responses

render() answers a request with a page component and its props:

return $this->inertia->render($request, $response, 'Event/Show', [
    'event' => ['id' => 80, 'title' => 'Birthday party'],
]);

It writes into the response it is given and returns it:

• A first visit — a browser request without X-Inertia — gets the HTML document of the root template, Content-Type: text/html; charset=utf-8.
• An Inertia visit gets the page object as JSON, with Content-Type: application/json and X-Inertia: true.

Both vary by X-Inertia. The status stays the response's own, so an error page is a page with a 404 or a 500:

return $this->inertia->render($request, $response->withStatus(404), 'Error', ['status' => 404]);

The page object

{
    "component": "Event/Show",
    "props": {"errors": {}, "event": {"id": 80, "title": "Birthday party"}},
    "url": "/events/80",
    "version": "c32b8e4965f418ad16eaebba1d4e960f",
    "sharedProps": ["errors"]
}

• url is the path and query string of the request.
• version is the asset version of the Inertia service.
• errors is in every page, {} without errors: see validation.
• Metadata such as deferredProps, mergeProps, onceProps, flash, encryptHistory appears only when a prop or an option needs it.

Props

A prop is any value json_encode() takes, and three more things:

Value	Sent
A value	As it is
A Closure	Its return value, called only when the response sends the prop
A JsonSerializable	What jsonSerialize() returns, resolved like any other value
A Prop	By its own rules: always, optional, deferred, merged, once, infinite scroll

Closures and Prop objects are resolved at any depth, and a Closure may return a Prop:

return $this->inertia->render($request, $response, 'Dashboard', [
    'user' => $user,                                     // always sent
    'teams' => fn() => $this->teams->of($user),          // sent when asked for, resolved then
    'auth' => [
        'notifications' => Inertia::defer(fn() => $this->notifications->unread($user)),
    ],
]);

Only a Closure is called: a string such as 'date' is a string, even though it names a function.

Dotted keys

A top-level key with dots nests into the prop it names, so a page can add to a shared prop:

Inertia::share($request, ['auth' => fn() => ['user' => $user]]);

return $this->inertia->render($request, $response, 'Account', [
    'auth.permissions' => ['edit'],   // props.auth = {user: ..., permissions: ["edit"]}
]);

A Closure on the way is called so the key can nest into what it returns; a value that is not an array there throws LogicException.

The component

The component is the page's name in the client, such as Tasks/Index for Pages/Tasks/Index.svelte. A string-backed enum works too:

enum Page: string
{
    case TasksIndex = 'Tasks/Index';
}

return $this->inertia->render($request, $response, Page::TasksIndex, $props);

Options

return $this->inertia->render($request, $response, 'Projects/Index', $props,
    flash: ['highlight' => $project->id], // one-time data for this page
    encryptHistory: true,                 // encrypt this page's history state
    clearHistory: true,                   // rotate the history encryption key
    viewData: ['title' => 'Projects'],    // for the root template only
);

• flash is this page's flash data, next to what a redirect left.
• encryptHistory and clearHistory are the history flags.
• viewData reaches the root template and never the client: meta tags, a CSP nonce.