Localize.js SEO prerendering middleware for Node.js

Usage no npm install needed!

<script type="module">
  import localizejsSeo from 'https://cdn.skypack.dev/localizejs-seo';


Localize SEO for Node.js

Node.js middleware that provides full SEO support for Node.js apps using Localize. This middleware detects requests from search engine bots and crawlers, and replies with prerendered HTML via our hosted prerendering API.

Questions? We're happy to help. Email us!.


Install via npm

npm install localizejs-seo --save

Add the Localize SEO middleware to your server:

var localizejsSEO = require('localizejs-seo');

  rootDomain: 'http://yourwebsite.com'

Include this middleware early in your application - before your application routes are created.


var localizejsSEO = require('localizejs-seo');

Creates the Localize SEO middleware. Accepted options:

  • rootDomain Required. The root domain of your website. For example, http://yourwebsite.com
  • version Optional. Cache version. Localize caches prerendered HTML for a number of hours. You can clear this cache immediately by changing the version when you deploy and update to your application. version can be a number or string like an application ID or git commit ID.
  • prerenderAllRequests Optional. When true, all requests are prerendered, not just requests from robots. Only useful for testing and debugging - do not activate in production.
  • shouldPrerenderOverride Optional. A function that overrides our internal shouldPrerender function. When this function returns true, the middleware will activate and prerender the route.

How it works

When a request is made to your server using this middleware, here's what happens:

  1. Middleware checks if request is a GET request. If not, next() is called and the middleware is bypassed.
  2. Middleware checks if request is made from a search engine bot or crawler (like Googlebot). If not, next() is called and the middleware is bypassed.
  3. When a GET request is made to your website by a search engine bot or crawler, the middleware makes a request to our prerendering API for the prerendered HTML of the page that was requested.
  4. The prerendered HTML is received from the localizejs.com API and delivered to the search engine crawler for indexing.

This is a hosted prerendering service, meaning that the prerendering of your page and caching is offloaded to our servers.


There are two built in layers of caching. We use Redis on our server to cache your HTML, and the reply is sent through the Amazon Cloudfront CDN to ensure extremely low latency response no matter where your server is (typically less than 20-50ms for a cached request).


Forks and pull requests welcome!


  • Add request timeout
  • Add tests


Localize. For support, email support@localizejs.com.