Invalid assetPrefix provided. Original error: ${error}

Error message

Invalid assetPrefix provided. Original error: ${error}

What it means

When `images.remotePatterns` is set AND `config.assetPrefix` starts with 'http', Next.js tries `new URL(config.assetPrefix)` to auto-add a remote pattern for the asset host (config.ts:727-746). If `new URL()` throws because the assetPrefix is not parseable as a URL, the catch wraps it in this error. This protects the optimizer from registering a malformed remote target.

Source

Thrown at packages/next/src/server/config.ts:743

      // so we need to ensure _next/image allows downloading from
      // this resource
      if (config.assetPrefix?.startsWith('http')) {
        try {
          const url = new URL(config.assetPrefix)
          const hasMatchForAssetPrefix = images.remotePatterns.some((pattern) =>
            matchRemotePattern(pattern, url)
          )

          // avoid double-pushing the same pattern if it already can be matched
          if (!hasMatchForAssetPrefix) {
            images.remotePatterns.push({
              hostname: url.hostname,
              protocol: url.protocol.replace(/:$/, '') as 'http' | 'https',
              port: url.port,
            })
          }
        } catch (error) {
          throw new Error(
            `Invalid assetPrefix provided. Original error: ${error}`
          )
        }
      }
    }

    if (images.domains) {
      if (!Array.isArray(images.domains)) {
        throw new Error(
          `Specified images.domains should be an Array received ${typeof images.domains}.\nSee more info here: https://nextjs.org/docs/messages/invalid-images-config`
        )
      }
    }

    if (!images.loader) {
      images.loader = 'default'
    }

View on GitHub (pinned to 0ae8c72462)

Solutions

Make assetPrefix a fully-qualified, parseable URL: `assetPrefix: 'https://cdn.example.com'`.
If assetPrefix is a path prefix (not a host), do not start it with 'http'.
Ensure any env vars interpolated into assetPrefix are set and non-empty.

Example fix

// before
module.exports = { assetPrefix: 'http://', images: { remotePatterns: [{ hostname: 'cdn.example.com' }] } }
// after
module.exports = { assetPrefix: 'https://cdn.example.com', images: { remotePatterns: [{ hostname: 'cdn.example.com' }] } }

Defensive patterns

Strategy: validation

Validate before calling

if (config.assetPrefix && config.assetPrefix.startsWith('http')) {
  try { new URL(config.assetPrefix); } catch (e) { throw new Error('assetPrefix is not a valid URL: ' + config.assetPrefix); }
}

Type guard

function isParseableHttpUrl(v: unknown): boolean {
  if (typeof v !== 'string' || !v.startsWith('http')) return true; // non-http prefixes skip this check
  try { new URL(v); return true; } catch { return false; }
}

Try / catch

try { new URL(config.assetPrefix); } catch (e) { throw new Error(`Invalid assetPrefix provided. Original error: ${e}`); }

Prevention

Validate templated assetPrefix values with `new URL()` before committing config.
Ensure env vars interpolated into assetPrefix are set and non-empty at build time.

When it happens

Trigger: Setting `assetPrefix: 'http://'` (empty host), `assetPrefix: 'http://[invalid'` (bad bracket), `assetPrefix: 'http://exa mple.com'` (space), or any assetPrefix starting with 'http' that is not a valid absolute URL, while also defining `images.remotePatterns`.

Common situations: Using a templated assetPrefix (e.g. `http://${BUCKET}`) where the env var is empty at build time. Typos in CDN URLs. Combining a custom assetPrefix with remotePatterns for the first time.

Related errors

AI-assisted analysis of vercel/next.js@0ae8c72462 (2026-08-06). Data as JSON: /api/errors/ef84d86fbe21cad2. Report an issue: GitHub.