next-sitemap

next-sitemap is a build-time CLI tool that generates sitemap.xml, sitemap indexes, and robots.txt for Next.js applications, covering static, pre-rendered, dynamic, and server-rendered pages alike. Run as a postbuild script, it scans the build output to enumerate pages automatically, then applies a next-sitemap.config.js file to control priorities, change frequencies, exclusions, and multi-sitemap splitting for large sites.

It handles the awkward cases that hand-written sitemaps miss: dynamic routes populated via getServerSideProps, i18n locale variants, and sites large enough to need sitemap indexes split across multiple files. Because it runs entirely from the CLI against build artifacts, it requires no runtime code changes to the application itself beyond a config file and a postbuild script entry.

What You Get

• A postbuild CLI command that generates sitemap.xml automatically after next build
• Support for static, dynamic, server-rendered, and i18n-localized page routes
• Automatic sitemap index splitting for large sites via a configurable page-count threshold
• robots.txt generation with configurable disallow rules and sitemap references
• A getServerSideSitemap helper for fully dynamic, on-demand sitemap generation
• Custom transform functions to set per-URL priority, changefreq, and lastmod values

Common Use Cases

• Generating a production sitemap.xml automatically as part of a Next.js CI/CD build pipeline
• Producing a robots.txt with environment-specific disallow rules (staging vs. production)
• Splitting a sitemap into multiple indexed files for a site with tens of thousands of pages
• Building a dynamic sitemap for a marketplace or blog where pages are generated from a database

Under The Hood

Architecture - The CLI entrypoint (packages/next-sitemap/src/cli.ts) runs a clear pipeline of single-purpose classes: ConfigParser loads next-sitemap.config.js and runtime paths, ManifestParser reads the Next.js build manifest to enumerate rendered pages, UrlSetBuilder turns that manifest into a normalized URL set applying per-page transforms, and ExportableBuilder chunks the set into sitemap files (splitting into an index when generateIndexSitemap is enabled) and writes robots.txt before exporting everything to disk. Tech Stack - A TypeScript monorepo managed with Turborepo and Bun workspaces (packages/next-sitemap, examples/*, docs), publishing dual ESM/CJS builds with generated type declarations, and depending on fast-xml-parser for sitemap XML generation. Code Quality - Each builder and parser has a colocated __tests__ directory with unit tests and Jest/Bun snapshot fixtures (e.g. generate-robots-txt.test.ts, create-url-set.test.ts, absolute-url.test.ts), and the test script runs with coverage in CI via azure-pipeline.yml, reflecting deliberate test coverage over the core sitemap/robots-txt generation logic. API Design - The tool’s primary interface is a single next-sitemap.config.js file plus a postbuild script entry, requiring no changes to application route code for static/SSR pages; the separate getServerSideSitemap helper extends the same design to fully dynamic routes without introducing a second configuration system.