Understanding getStaticPaths in Next.js

Dynamic routes are one of the best parts of Next.js, but they raise an immediate follow‑up question when we want static generation:

If one file can represent many routes, which specific routes should Next.js build ahead of time?

That is the job of getStaticPaths.

It works together with getStaticProps for dynamic pages and tells Next.js which path parameters should be generated during the build.

getStaticPaths is for dynamic routes

This function only makes sense on dynamic route pages, such as:

pages/articles/[slug].tsx

Because the route is dynamic, Next.js needs to know which concrete slugs should exist as pre‑rendered static pages.

That information is what getStaticPaths provides.

If dynamic routes still feel a bit hand‑wavy at this point, it is worth reading Dynamic Routes in Next.js alongside this. getStaticPaths makes much more sense once the routing side is properly grounded.

The Basic Shape

Here is a simplified example:

import type { GetStaticPaths, GetStaticProps } from 'next';type ArticlePageProps = {  slug: string;};export const getStaticPaths: GetStaticPaths = async () => {  return {    paths: [      { params: { slug: 'accessibility-basics' } },      { params: { slug: 'seo-tips' } },    ],    fallback: false,  };};export const getStaticProps: GetStaticProps<ArticlePageProps> = async ({  params,}) => {  return {    props: {      slug: params?.slug as string,    },  };};const ArticlePage = ({ slug }: ArticlePageProps): JSX.Element => {  return <h1>{slug}</h1>;};export default ArticlePage;

The paths array declares which concrete URLs should be built.

That becomes especially important once you are dealing with real editorial or location‑driven content. On the Nando’s UK & Ireland Replatform, prebuilding the right paths was part of keeping a large content estate fast without giving up flexibility.

Why This is Necessary

With a static page like pages/about.tsx, the route is obvious and singular.

With pages/articles/[slug].tsx, the route is a pattern rather than a final URL. Next.js cannot guess every possible slug from the file name alone. It needs actual values.

That is why getStaticPaths exists as a separate step.

paths and params mirror the route segments

If the dynamic file is [slug].tsx, each path entry needs a slug value.

If the route were:

pages/shop/[category]/[product].tsx

then each path entry would need both:

• category
• product

This is another place where the file structure and the route data stay pleasantly aligned.

getStaticPaths and getStaticProps work as a pair

The former answers:

"Which dynamic routes should exist as static pages?"

The latter answers:

"What props should each of those pages receive?"

That pairing is what makes static generation work for dynamic content such as blogs, product pages, and CMS‑driven entries.

CMS‑Driven Sites are a Natural Fit

Imagine a headless CMS containing article entries with slugs.

getStaticPaths can fetch the list of published slugs, while getStaticProps fetches the content for each individual slug during the build.

That is a very clean model for content sites:

• collect all the route IDs
• build all the matching pages

This is one of the reasons Next.js became so popular for editorial and marketing work.

fallback controls what happens for paths not returned at build time

In the simplest configuration, fallback: false means only the listed paths exist. Any other route matching the pattern becomes a 404.

That is often perfectly appropriate when:

• the content list is known at build time
• every valid page can be generated up front
• unknown paths should simply not exist

This mode is easy to reason about because the build output matches the provided list exactly.

fallback: true allows more flexibility

With fallback: true, paths not generated during the initial build can still be handled later.

That can be useful when:

• the list is large
• content is growing frequently
• building every possible route up front would be inefficient

The trade‑off is that the page now needs to handle a fallback state when the full content has not been generated yet.

That means the UI logic becomes a little more involved.

Fallback Strategy is Part of Product Behaviour, Not Just Framework Wiring

This is easy to miss.

If a user visits a route that was not pre‑rendered initially, what experience should they have?

• immediate 404
• loading shell
• delayed full render later

These are not only technical choices. They shape how complete and responsive the application feels.

Static Generation Does Not Remove Route Design Responsibility

Even with getStaticPaths, we still need to think carefully about:

• which routes should exist
• whether the slug list is trustworthy
• how missing content should behave
• how large the path set may become over time

The framework helps with mechanics. It does not decide the shape of the content model for us.

A Useful Way to Think About It

getStaticPaths is the routing inventory step for static dynamic pages.

It answers:

"Give me the concrete route list for this dynamic template."

That is a very practical job, and seeing it that way tends to make the feature less intimidating.

The Function is About Certainty

Static generation works best when the build knows what it is preparing.

getStaticPaths gives Next.js that certainty for dynamic routes. Instead of saying "there is some route pattern here", we say "here are the actual pages that should be generated from that pattern".

That is why the function matters so much in content‑driven builds.

Dynamic Pages Still Need a Build List

getStaticPaths is the missing piece that makes dynamic routes and static generation work together in Next.js. It turns a route pattern into a concrete list of pre‑rendered pages and lets the build process treat dynamic content with much more confidence.

Once you understand that role, the feature becomes less of an extra API to memorise and more of a natural step in how static dynamic pages get built.