How to Tell if a Website Is Built with Next.js

Next.js is one of the most popular React frameworks, powering thousands of high-traffic websites from startups to enterprise companies. Knowing how to detect a Next.js website is valuable for developers studying best-in-class implementations, teams doing competitive research, and technical evaluators assessing a site's infrastructure. Here's how to identify Next.js definitively.

Why Next.js Is Worth Detecting

Next.js sites tend to be technically sophisticated. Identifying that a competitor or inspiring site uses Next.js tells you:

They have React development capability in-house (or hired it)

They're prioritizing performance (Next.js has excellent SSR/SSG capabilities)

They're likely hosted on Vercel, AWS, or similar infrastructure

Their SEO strategy relies on server-side rendering or static generation

Method 1: AIWebsiteDetector.com

Scan any URL at AIWebsiteDetector.com for instant Next.js detection. The tool checks HTTP headers, JavaScript bundle patterns, and routing signatures that identify Next.js specifically.

Method 2: Check HTTP Response Headers

Next.js on Vercel (the most common deployment) adds a distinctive header:

x-powered-by: Next.js

To check HTTP headers:

Open DevTools (F12)

Go to the Network tab

Reload the page

Click on the first request (the main document)

Look in the Response Headers section

The x-powered-by: Next.js header is present on many Next.js deployments, though some teams disable it for security reasons using poweredByHeader: false in next.config.js.

Vercel also adds:

server: Vercel

A site on Vercel with Next.js headers is a very strong combined signal.

Method 3: Look for __NEXT_DATA__

Every server-rendered Next.js page injects a script tag containing initial page data:

Search the page source for __NEXT_DATA__. This is one of the most reliable Next.js fingerprints because it's fundamental to how Next.js hydrates the client-side React app with server-rendered data. It appears on virtually every SSR Next.js page.

Method 4: Check JavaScript Bundle Paths

Next.js generates JavaScript bundles with a distinctive path structure:

The /_next/static/ path is unique to Next.js. No other framework uses this exact path structure. Search the page source for /_next/ — if it appears, the site is built with Next.js.

Even for statically exported Next.js sites (deployed without a Node.js server), this path structure is preserved in the built output.

Method 5: Check for Next.js Routing Patterns

Next.js has a distinctive URL and routing behavior:

API routes: /api/[endpoint] — Next.js API routes follow this pattern

Dynamic routes: URLs like /blog/[slug] with consistent structure

404 page: Next.js default 404 pages have a specific structure

Try navigating to /api/health or another common API endpoint path — a JSON response suggests an active Next.js API route.

Method 6: Check for next/image Patterns

Next.js has a built-in image optimization component. Images optimized by Next.js are served via:

Or as a Next.js 13+ blur placeholder:

The /_next/image URL pattern is definitive.

Comparison of Next.js Detection Signals

| Signal | Reliability | Where to Find |

Gatsby (React, static): Uses /static/ paths and page-data.json files

Remix (React): Different routing and no __NEXT_DATA__ pattern

SvelteKit: Uses /_app/ paths

The /_next/ prefix is unique to Next.js among major frameworks.

What Companies Use Next.js?

Next.js is used by some of the most well-known sites on the web:

TikTok (web version)

Hulu

Twitch (parts of the site)

Vercel (their own site, naturally)

Notion

OpenAI (openai.com)

Many high-growth SaaS companies choose Next.js for its excellent performance, SEO capabilities, and large developer ecosystem.

Frequently Asked Questions

Does Next.js always leave detectable traces?

Almost always. The /_next/static/ path in JavaScript bundle references is present in virtually every Next.js deployment because it's how Next.js serves its built assets. The __NEXT_DATA__ script is present on all SSR pages. Static export mode removes some signals but leaves the bundle path structure.

How can I tell Next.js version?

The buildId field inside __NEXT_DATA__ is unique per build but doesn't contain the version number. You can sometimes find the version in JavaScript comments or source maps, but this isn't reliably accessible.

Is Next.js the same as React?

No. React is a JavaScript library for building UIs. Next.js is a framework built on top of React that adds server-side rendering, file-based routing, API routes, and build optimization. All Next.js apps use React, but not all React apps use Next.js.

What's the difference between Next.js and Vercel?

Vercel is the hosting platform created by the same team that maintains Next.js. Next.js is the framework; Vercel is one deployment option (though Next.js can be deployed anywhere Node.js runs). Many Next.js sites are on Vercel because the integration is seamless.

Can Next.js be used for e-commerce?

Yes. Next.js with Shopify's Storefront API (headless Shopify) is a popular pattern for high-performance e-commerce sites. These sites are Next.js on the frontend with Shopify as the backend — the frontend looks like Next.js while the commerce infrastructure is Shopify.

Scan Sites Instantly

Use AIWebsiteDetector.com to detect Next.js sites along with WordPress, Webflow, Shopify, Framer, and dozens of other technologies. The scanner is built for developers and researchers who want quick, reliable technology identification without manual source code inspection.