Bug report

• I confirm this is a bug with Supabase, not with my own application.
• I confirm I have searched the Docs, GitHub Discussions, and Discord.

Describe the bug

@supabase/ssr’s createBrowserClient internally pulls in @supabase/auth-js, which calls Math.random() during startup to generate a UUID. In Next.js 16 App Router, Server Components must remain deterministic until they’ve read an uncached data source; touching Math.random() before that triggers the new runtime guard. The moment I import the client inside a Server Component (or a non-cached shared component like the site header), the app fails at build/runtime with:

Route "/" used `Math.random()` before accessing either uncached data ... See more info here:
https://nextjs.org/docs/messages/next-prerender-random
.../node_modules/@supabase/auth-js/src/lib/helpers.ts (14:21)

This happens even if I never issue a query—the act of instantiating the client is enough.

To Reproduce

1. Create a fresh Next.js 16 (App Router, Cache Components) project and install @supabase/ssr 0.7.0 (or current).

2. Add a file lib/supabase-client.ts:

   import { createBrowserClient } from "@supabase/ssr";
   import type { Database } from "./types";
   
   export const supabase = createBrowserClient<Database>(
     process.env.NEXT_PUBLIC_SUPABASE_URL!,
     process.env.NEXT_PUBLIC_SUPABASE_PUBLISHABLE_KEY!
   );

3. Import that module from any Server Component that renders on /, e.g. a shared header:

   // app/components/header.tsx
   "use client";
   
   import { supabase } from "@/lib/supabase-client";
   
   export function Header() {
     // no queries needed – just referencing the client triggers the guard
     return <div>Header</div>;
   }

4. Run pnpm dev (or build). The dev overlay shows the Math.random() error coming from @supabase/auth-js.

Expected behavior

Instantiating a Supabase browser client in a Server Component should not break deterministic rendering in Next.js 16.

Screenshots

System information

• OS: Windows
• Versions: using latest versions of next (16) @supabase/ssr, @supabase/supabase-js and @supabase/postgrests-js.
• Version of Node.js: v22

Additional context

Related issue: https://www.answeroverflow.com/m/1432792611617247435