Fix /webmail 404 on Vercel in 10 Minutes (SiteGround/Hostinger)

Use this when your domain points to Vercel but your email stays at SiteGround, Hostinger, or cPanel hosting.

Related deep-dive: How to Fix SiteGround Webmail 404 on Vercel.

Prerequisites

Next.js App Router project
webmail host URL from your provider
deploy access to Vercel

Step-by-Step

Step 1: Create route files

Create this structure:

TEXT

app/webmail/route.ts
app/webmail/[...slug]/route.ts

Step 2: Add root redirect

import { NextResponse } from "next/server";

export const runtime = "edge";
const WEBMAIL_BASE = "https://your-webmail-host.example/webmail";

export function GET() {
  return NextResponse.redirect(`${WEBMAIL_BASE}/`, 307);
}

Step 3: Add catch-all redirect

import { NextResponse } from "next/server";
import type { NextRequest } from "next/server";

export const runtime = "edge";
const WEBMAIL_BASE = "https://your-webmail-host.example/webmail";

export function GET(
  request: NextRequest,
  { params }: { params: { slug: string[] } }
) {
  const tail = `/${params.slug.join("/")}`;
  const query = request.nextUrl.search;

  return NextResponse.redirect(`${WEBMAIL_BASE}${tail}${query}`, 307);
}

Step 4: Deploy and verify

Test both URLs:

TEXT

https://yourdomain.com/webmail/
https://yourdomain.com/webmail/mail?token=...

Both should forward to your provider's webmail host.

Validation Checklist

Query token is preserved.
No 404 for nested /webmail/* paths.
No logged token values in server logs.
MX records remain unchanged.

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