Add getSiteUrl() for automatic Vercel OG image URL detection

OG images now work automatically on Vercel without manual URL configuration.
Priority: NEXT_PUBLIC_SITE_URL > VERCEL_URL > siteConfig.url

Author: gregce

packages/create-unmint/package.json

@@ -1,6 +1,6 @@
 {
   "name": "create-unmint",
-  "version": "1.3.1",
+  "version": "1.3.2",
   "description": "Create a new Unmint documentation project",
   "type": "module",
   "bin": {

packages/template/app/docs/[[...slug]]/page.tsx

@@ -6,7 +6,7 @@ import { getMDXComponents } from '../../components/docs/mdx'
 import { findNeighbour } from 'fumadocs-core/page-tree'
 import type { Metadata } from 'next'
 import type { Root, Node } from 'fumadocs-core/page-tree'
-import { siteConfig, themeConfig } from '@/lib/theme-config'
+import { getSiteUrl } from '@/lib/theme-config'
 
 interface PageProps {
   params: Promise<{ slug?: string[] }>
@@ -108,7 +108,9 @@ export async function generateMetadata({ params }: PageProps): Promise<Metadata>
   const description = page.data.description
 
   // Build OG image URL with query params
-  const ogImageUrl = new URL(`${siteConfig.url}/api/og`)
+  // getSiteUrl() auto-detects Vercel deployments
+  const baseUrl = getSiteUrl()
+  const ogImageUrl = new URL(`${baseUrl}/api/og`)
   ogImageUrl.searchParams.set('title', title)
   ogImageUrl.searchParams.set('section', section)
 
@@ -119,7 +121,7 @@ export async function generateMetadata({ params }: PageProps): Promise<Metadata>
       title,
       description,
       type: 'article',
-      url: `${siteConfig.url}${page.url}`,
+      url: `${baseUrl}${page.url}`,
       images: [
         {
           url: ogImageUrl.toString(),

packages/template/lib/theme-config.ts

@@ -87,3 +87,18 @@ export function getCSSVariables(mode: 'light' | 'dark') {
     '--accent-muted': colors.accentMuted,
   }
 }
+
+/**
+ * Get the site URL dynamically
+ * Priority: NEXT_PUBLIC_SITE_URL > VERCEL_URL > siteConfig.url
+ * This allows OG images to work automatically on Vercel without configuration
+ */
+export function getSiteUrl(): string {
+  if (process.env.NEXT_PUBLIC_SITE_URL) {
+    return process.env.NEXT_PUBLIC_SITE_URL
+  }
+  if (process.env.VERCEL_URL) {
+    return `https://${process.env.VERCEL_URL}`
+  }
+  return siteConfig.url
+}