Proxy sitemaps within sitemap index for prettier sitemap URLs

[bookernath]

What/Why?

Catalyst's sitemap was using the channel canonical URL for the internal sitemap URLs, in order to avoid the complexity of proxying these internally via Catalyst itself and provide a reliable way to fetch them. Research shows this is OK for SEO, but we've received a steady stream of customer feedback indicating that having internal sitemap URLs that match the domain of the website is preferable.

This PR does that, by proxying the sitemap index, rewriting the internal URLs for the sitemap to live on https://store.com/sitemap.xml?..., and then proxies those requests for the actual sitemaps as well.

Since Next.js does not provide a variable to easily understand the "production" hostname for the app, I am relying on on the Host header for this.

Based on feedback from @apledger I have extracted it into its own package to abstract the complexity and make it easier to update later via a version bump.

Testing

Before, from https://catalyst-canary.store/sitemap.xml

<sitemapindex xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/siteindex.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
--
<sitemap>
<loc>https://store-vcijajnodd-1543376.mybigcommerce.com/xmlsitemap.php?type=pages&amp;page=1</loc>
</sitemap><sitemap>
<loc>https://store-vcijajnodd-1543376.mybigcommerce.com/xmlsitemap.php?type=products&amp;page=1</loc>
</sitemap><sitemap>
<loc>https://store-vcijajnodd-1543376.mybigcommerce.com/xmlsitemap.php?type=categories&amp;page=1</loc>
</sitemap><sitemap>
<loc>https://store-vcijajnodd-1543376.mybigcommerce.com/xmlsitemap.php?type=brands&amp;page=1</loc>
</sitemap><sitemap>
<loc>https://store-vcijajnodd-1543376.mybigcommerce.com/xmlsitemap.php?type=news&amp;page=1</loc>
</sitemap>
</sitemapindex>

After, on https://catalyst-canary-3e4nxxptx-bigcommerce-platform.vercel.app/sitemap.xml

<sitemapindex xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/siteindex.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
--
<sitemap>
<loc>https://catalyst-canary-3e4nxxptx-bigcommerce-platform.vercel.app/sitemap.xml?type=pages&amp;page=1</loc>
</sitemap><sitemap>
<loc>https://catalyst-canary-3e4nxxptx-bigcommerce-platform.vercel.app/sitemap.xml?type=products&amp;page=1</loc>
</sitemap><sitemap>
<loc>https://catalyst-canary-3e4nxxptx-bigcommerce-platform.vercel.app/sitemap.xml?type=categories&amp;page=1</loc>
</sitemap><sitemap>
<loc>https://catalyst-canary-3e4nxxptx-bigcommerce-platform.vercel.app/sitemap.xml?type=brands&amp;page=1</loc>
</sitemap><sitemap>
<loc>https://catalyst-canary-3e4nxxptx-bigcommerce-platform.vercel.app/sitemap.xml?type=news&amp;page=1</loc>
</sitemap>
</sitemapindex>

Internal URLs also work.

Migration

N/A

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Latest commit: d3318d0

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Project	Deployment	Preview	Comments	Updated (UTC)
catalyst-b2b	Ready	Preview	Comment	Nov 21, 2025 10:31pm
catalyst-canary	Ready	Preview	Comment	Nov 21, 2025 10:31pm

4 Skipped Deployments

Project	Deployment	Preview	Comments	Updated (UTC)
catalyst	Ignored			Nov 21, 2025 10:31pm
catalyst-au	Ignored			Nov 21, 2025 10:31pm
catalyst-uk	Ignored			Nov 21, 2025 10:31pm
catalyst-uplift-vertex	Ignored			Nov 21, 2025 10:31pm