SEO and Angular: is not the cure


I heard of the “” service quite a while back, but for some reason, it looks like it became popular recently on some blogs.

Prerender promises to optimize your AngularJS app for Google and friends! Nice!

Here are a few thoughts.

No cure, still

Prerender uses deprecated technology

But if you are super serious about the business of SEO optimization, I think you should be very careful to use that tool.

First off, Prerender said it is using a specification from Google which defines Ajax crawling. But this specification is deprecated. In a blog post google does not longer recommend to use the specification anymore:

Today, as long as you’re not blocking Googlebot from crawling your JavaScript or CSS files, we are generally able to render and understand your web pages like modern browsers.

In other terms: Google learned. No more action needed. Unfortunately, it seems Bing is not as good as Google. If you really, really want to optimize for Bing as well, you could still consider Here is the estimated market share for search engines, decide on your own if you need the 15% (I assume your website is not in chinese).

Prerender could cause cloaking

Cloaking is happening, when a website displays different content to users than to search engines. At least, Google is fast with penalties if you are cloaking.

Google says:

When evaluating your site to see if it includes hidden text or links, look for anything that’s not easily viewable by visitors of your site. Are any text or links there solely for search engines rather than visitors?

Please test, test, test each and any of your websites for cloaking, esp when serving two different versions of it! I would not believe there is zero differences for halfway complex websites.

Canonical URLs and duplicate content

I have not seen an example on itself, but you need to test if your URLs change for the rendered version and the JavaScript version. If it does, then you are generating duplicate content.

Duplicate content is one of the worst things a website can have, besides cloaking.

Angular provides a very nice “page switching” mechanism, and I bet a lot of people are using it.

API errors

What if your API returns an error? Read the best practices what to do…


Whatever you do or need, making SEO “optimized” websites across all search engines is tricky. Prerender suggests it is an easy, trivial task, but if you are serious about it, I would not believe it.

You can skip the tool in full if your JS is half way sane and if the 65% marketshare of Google convinces you. I would assume Bing has something in the makings to also crawl JS sites, but for now… it’s not.

Google Page Speed test for Prerender

In general, the Prerender website fails hard in the Google page speed test, at least as of today. Offering a “cached blazing fast” solution let’s me yawn when I get a single file served in more than 1 second and Google complains. The website itself is definitely not “optimized”.

At the moment there is only one solution: make a parseable website enhanced with some JavaScript maybe. If you optimize for search engines, you should stay away from Angular and friends. At least, calculate some budget for properly setting up a service like Sorry, no Unicorns.


Tags: #Google #SEO #Angular #JavaScript