sveltejs/kit · error · Error

Cannot call a command (${__.name}) during server-side render

Error message

Cannot call a command (${__.name}) during server-side rendering

What it means

Runtime guard around a remote command: the request-store state marks the current execution as server-side rendering (is_in_render). Commands mutate state and require a real mutative request, so invoking one during SSR (e.g. at component init while rendering) is rejected.

Source

Thrown at packages/kit/src/runtime/app/server/remote/command.js:82

	/** @type {RemoteCommand<Input, Output> & { __: RemoteCommandInternals }} */
	const wrapper = (arg) => {
		const { event, state } = get_request_store();

		if (
			!MUTATIVE_METHODS.includes(event.request.method) ||
			state.is_in_remote_query ||
			state.is_in_remote_prerender
		) {
			const violation =
				state.is_in_remote_query || state.is_in_remote_prerender
					? `inside a query or prerender function`
					: `from a ${event.request.method} handler`;

			throw new Error(`Cannot call a command (${__.name}) ${violation}`);
		}

		if (state.is_in_render) {
			throw new Error(`Cannot call a command (${__.name}) during server-side rendering`);
		}

		const promise = Promise.resolve(
			run_remote_function(event, state, true, () => validate(arg), fn)
		);

		// @ts-expect-error
		promise.updates = () => {
			throw new Error(`Cannot call '${__.name}(...).updates(...)' on the server`);
		};

		return /** @type {ReturnType<RemoteCommand<Input, Output>>} */ (promise);
	};

	Object.defineProperty(wrapper, '__', { value: __ });

	// On the server, pending is always 0
	Object.defineProperty(wrapper, 'pending', {

View on GitHub (pinned to 03f1687fe6)

Solutions

  1. Move the command call into a user-triggered event handler (form submit, button click) or a load/query function
  2. Avoid invoking commands during component initialization on the server
Defensive patterns

Strategy: validation

When it happens

Trigger: Thrown at packages/kit/src/runtime/app/server/remote/command.js:82 when the library encounters an invalid state.

Common situations: See trigger scenarios.


AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/0d2e09c228f86538. Report an issue: GitHub.