Incorrect metadata canonical URL when using next-intl and opennextjs, could anyone help?

[enterwiz]

Hi, guys! 👋 I’ve been struggling with an i18n metadata issue when using next-intl and would really appreciate some guidance from the community.

Brief context

I try to migrate nextjs project to cloudflare workers. The project uses opennextjs as the adapter, and next-intl for i18n. When using next-intl in as-needed mode, the canonical URL in metadata shows the correct path (https://mysite.com/) during next dev, but incorrectly appends the default locale (/en) during next preview or production builds. This violates the as-needed mode specification where default locales shouldn't appear in URLs.

Steps to reproduce

Create a Next.js project with nextjs, opennextjs and next-intl (v3+)

Configure i18n with as-needed mode:

// i18n/routing.ts

import { defineRouting } from 'next-intl/routing';
import { defaultLocale, locales } from '@/data/config/locales';

export const routing = defineRouting({
  // A list of all locales that are supported
  locales: Object.keys(locales),
  defaultLocale: defaultLocale,
  localePrefix: 'as-needed',
});

Set metadata with relative canonical:

// app/[locale]/layout.tsx
const metadata: Metadata = {
  metadataBase: new URL('https://mysite.com'),
  alternates: { canonical: './' }
};

Run next dev → Open /en → Canonical shows https://mysite.com/ (correct)
Run opennextjs-cloudflare build && opennextjs-cloudflare preview → Open /en → Canonical shows https://mysite.com/en (incorrect)

Expected behavior

Canonical URL should consistently omit default locale prefixes in as-needed mode across all environments:

Dev: https://mysite.com/
Preview/Production: https://mysite.com/

Environment

nextjs version: 15.3.3
@opennextjs/cloudflare version: 1.0.4
Wrangler version: 4.19.1
next-intl version: 4.1.0

__

Question

Could anyone help me diagnose this? Specifically looking for:

• Known solutions for static exports
• Workaround experiences
• Whether this might be a library limitation

Thanks so much for your time! Any pointers would be incredibly helpful 🙏

[amannn]

If you're using as-needed, I guess you don't want a locale prefix for your default locale, but you do in fact want it for other locales—right? I guess a static metadata export won't do the job here.

What you could do is using generateMetadata to dynamically compute alternates and use the getPathname from next-intl that will incorporate your routing strategy based on a provided locale.

[enterwiz]

I’d like to centrally configure the canonical URL using a ​​relative path​​ (./) in layout.tsx to ​​dynamically generate canonical URLs for all pages​​. This approach is highly convenient since it eliminates the need to manually set them in each page individually.

While generateMetadata() could achieve this dynamically at the page level, it would admittedly be less streamlined.

Is there a better way to achieve this?

[amannn]

Not that I'm aware of. I think declaring canonicals on each page where they're needed is likely necessary.