sveltejs/kit · error · Error

read(...) failed: could not fetch ${url} (${response.status}

Error message

read(...) failed: could not fetch ${url} (${response.status} ${response.statusText})

What it means

In Netlify Edge Functions, the SvelteKit server's read() function (used by e.g. imports of files at runtime via the $app/server read API) fetches static assets from the origin over HTTP instead of reading from disk (Deno edge runtime has no filesystem access). If the fetch to `${origin}/${file}` returns a non-OK response, this error is thrown with the URL and HTTP status.

Source

Thrown at packages/adapter-netlify/files/edge.js:17

import { server } from '0SERVER';

/**
 * We don't know the origin until we receive a request, but
 * that's guaranteed to happen before we call `read`
 * @type {string}
 */
let origin;

const initialized = server.init({
	env: Deno.env.toObject(),
	read: async (file) => {
		const url = `${origin}/${file}`;
		const response = await fetch(url);

		if (!response.ok) {
			throw new Error(
				`read(...) failed: could not fetch ${url} (${response.status} ${response.statusText})`
			);
		}

		return response.body;
	}
});

/** @type {import('@netlify/edge-functions').EdgeFunction} */
export default async function handler(request, context) {
	if (!origin) {
		origin = new URL(request.url).origin;
	}

	// always await initialization to prevent race condition with concurrent requests
	await initialized;

	return server.respond(request, {

View on GitHub (pinned to 03f1687fe6)

Solutions

Verify the file exists in the site's published static/publish directory before calling read()
Fix the path passed to read() — it must match the deployed asset path exactly (no leading slash issues)
If the file is generated at runtime, store it in Netlify Blobs or an external store instead of relying on read()
Wrap the call in try/catch and handle non-200 responses gracefully

Example fix

// before
const file = await read(`${params.slug}.json`);
// after
let file;
try {
  file = await read(`${params.slug}.json`);
} catch (e) {
  throw error(404, 'Asset not found');
}

Defensive patterns

Strategy: try-catch

Validate before calling

const res = await fetch(`${origin}/${file}`, { method: 'HEAD' });
if (!res.ok) console.warn(`Asset ${file} not deployed (HTTP ${res.status})`);

Try / catch

try {
  const stream = await read(filePath);
} catch (err) {
  if (err.message.startsWith('read(...) failed')) {
    throw error(404, `Asset not available: ${filePath}`);
  }
  throw err;
}

Prevention

Ensure every file passed to read() exists in the published static assets
Never call read() for runtime-generated files — use Netlify Blobs or KV instead
Log the failing URL/status from the error to distinguish 404 (missing asset) from 5xx (origin issue)

When it happens

Trigger: Calling read('path') from an edge function for a file that does not exist in the published static assets (404), or the origin returning 403/500; requesting a path outside the deployed static directory.

Common situations: Edge function reading a user-uploaded or generated file that was never deployed; typo in the file path; file present locally but excluded from the build output; Netlify origin briefly erroring (5xx).

Related errors

AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/d82c1ec328683820. Report an issue: GitHub.