sveltejs/kit · error · Error

Tracing is enabled (see the SvelteKit plugin `tracing.server

Error message

Tracing is enabled (see the SvelteKit plugin `tracing.server` option in your vite.config.js), but `@opentelemetry/api` is not available. This error will likely resolve itself when you set up your tracing instrumentation in `instrumentation.server.js`. For more information, see https://svelte.dev/docs/kit/observability#opentelemetry-api

What it means

When tracing is enabled via the SvelteKit plugin's `tracing.server` option, SvelteKit imports `@opentelemetry/api` to create spans. If that package cannot be resolved, initialization fails with this error, directing you to set up tracing instrumentation (typically in `instrumentation.server.js`) which registers the provider.

Source

Thrown at packages/kit/src/exports/internal/server/telemetry.js:29

/**
 * The caller passes in `import('@opentelemetry/api')` so the import lives behind
 * `__SVELTEKIT_SERVER_TRACING_ENABLED__` in the bundled runtime and is eliminated
 * from builds with tracing disabled, where the package may not be installed.
 * @param {Promise<typeof import('@opentelemetry/api')>} api
 * @returns {void}
 */
export function init_tracing(api) {
	otel ??= api
		.then((module) => {
			return {
				tracer: module.trace.getTracer('sveltekit'),
				propagation: module.propagation,
				context: module.context,
				SpanStatusCode: module.SpanStatusCode
			};
		})
		.catch(() => {
			throw new Error(
				'Tracing is enabled (see the SvelteKit plugin `tracing.server` option in your vite.config.js), but `@opentelemetry/api` is not available. This error will likely resolve itself when you set up your tracing instrumentation in `instrumentation.server.js`. For more information, see https://svelte.dev/docs/kit/observability#opentelemetry-api'
			);
		});
}

/** @type {RecordSpan} */
export async function record_span({ name, attributes, fn }) {
	if (otel === null) {
		return fn(noop_span);
	}

	const { SpanStatusCode, tracer } = await otel;

	return tracer.startActiveSpan(name, { attributes }, async (span) => {
		try {
			return await fn(span);
		} catch (error) {
			if (error instanceof HttpError) {

View on GitHub (pinned to 03f1687fe6)

Solutions

1. Install the package: `npm install @opentelemetry/api` (add it to production dependencies).
2. Create/complete `instrumentation.server.js` to register a span processor/exporter per the SvelteKit observability docs.
3. If you don't want tracing, disable the `tracing.server` plugin option.
4. Rebuild/redeploy after installing so the server bundle can resolve the module.

Example fix

// before (svelte.config.js)
kit: { experimental: { tracing: { server: true } } }
// after
// terminal: npm i @opentelemetry/api
// instrumentation.server.js
import { NodeSDK } from '@opentelemetry/sdk-node';
export const handleInstrumentation = (sdk = new NodeSDK()) => sdk.start();

let api;
try {
  api = await import('@opentelemetry/api');
} catch {
  api = null; // tracing unavailable — disable or install the package
}
if (!api) console.warn('tracing.server enabled but @opentelemetry/api missing');

try {
  await init_tracing();
} catch (e) {
  if (String(e.message).includes('@opentelemetry/api')) {
    console.warn('Tracing disabled: install @opentelemetry/api or turn off tracing.server');
  } else throw e;
}

When it happens

Trigger: Setting `tracing.server` in `svelte.config.js`/vite plugin options without `@opentelemetry/api` installed; the package is in devDependencies but the server is bundled/deployed without it; a broken node_modules after version changes.

Common situations: Enabling observability in production deployments where `@opentelemetry/api` wasn't added to production dependencies; monorepo hoisting issues hiding the package; forgetting `instrumentation.server.js` setup that registers a tracer provider.

Understand the failure class

Background: "not installed", "pip install", "required for": how missing-dependency errors surface across open-source libraries — this error's family across 34 libraries.

Related errors

• exports is not available in dev mode
• The `generateManifest` adapter API has been removed — use `g
• Instrumentation file ${instrumentation} not found. This is p
• Entrypoint file ${entrypoint} not found. This is probably a
• Instrumentation initializer ${initializer} not found. This i

AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/25357852108303b2. Report an issue: GitHub.