We have seen more than 2,500 domains that are struggling with indexing.
The indexing rate often depends on the quality of the page, your domain and if there’s currently a big google update going on.
Good domains achieve an indexing rate of 80% while poor domains can even end of with 0% indexed.

Before we go into why your pages don’t get indexed please note:
Building more pages does not mean more clicks.
We regularly audit large marketplaces and one of the first things we do it removing hundreds of thousands of pages.
This is what happened after we have removed 600,000 (useless) pages:

The existing pages start to rank higher and in general more pages overall start to rank.
Impressions and clicks are up after removing hundreds of thousands of pages.

Before we discuss indexing issues and how to fix them, it’s important to understand what indexing issues are not.
The following are not indexing issues
Part 1: Not all your pages should be indexed
Websites that generate many pages through code often have hundreds of thousands of pages that should not be indexed.
This is true for marketplaces and e-commerce.
- For e-commerce, if you sell a sling bags, you don’t need to have 100 a page for every single variation of the sling bag. 
Specifically, you do not need to index these pages:
- /custom-sling-bag-in-gray-extra-extra-large 
- /custom-sling-bag-in-gray-extra-large 
- /custom-sling-bag-in-gray-large 
- /custom-sling-bag-in-gray-medium-large 
- /custom-sling-bag-in-gray-medium-plus 
- /custom-sling-bag-in-gray-medium 
- /custom-sling-bag-in-gray-medium-small 
- /custom-sling-bag-in-gray-medium-small-small 
- /custom-sling-bag-in-gray-small 
- /custom-sling-bag-in-gray-xs-small 
- /custom-sling-bag-in-gray-very-small 
- /custom-sling-bag-in-gray-very-very-small 
- /custom-sling-bag-in-gray-very-very-very-small 
and you also don’t need to do it even if it’s black:
- /custom-sling-bag-in-black-extra-extra-large 
- /custom-sling-bag-in-black-extra-large 
- /custom-sling-bag-in-black-large 
- /custom-sling-bag-in-black-medium-large 
- /custom-sling-bag-in-black-medium-plus 
- /custom-sling-bag-in-black-medium 
- /custom-sling-bag-in-black-medium-small 
- /custom-sling-bag-in-black-medium-small-small 
- /custom-sling-bag-in-black-small 
- /custom-sling-bag-in-black-xs-small 
- /custom-sling-bag-in-black-very-small 
- /custom-sling-bag-in-black-very-very-small 
- /custom-sling-bag-in-black-very-very-very-small 
More scenarios
- For marketplaces, you don’t need to index all the user profiles (rosy8191) that have ever signed up. 
- As a job portal, you shouldn’t index jobs that were posted 5 years ago. 
- As a property marketplace, you don’t need to generate millions of pages like - middle-road-23-central-businsess-district-apparement-between-1500-and-1550 
- middle-road-23-central-businsess-district-apparement-between-1550-and-1600 
- middle-road-23-central-businsess-district-apparement-between-1600-and-1650 
- etc. 
 
Consider if the pages really should be indexed and if they add value to your visitor. If not, just add a “noindex” tag to them.
Part 2: AI slob and very short content
If your content is mass ai AI-generated, it’s likely very bland and not helpful to the user at all. It might index initially, but over time, your domain will likely get shadow-banned. This is not an official penalty, your pages are simply removed from the indexed.
This is an extreme example:

The website had hundreds of thousands of AI-generated pages. Once your domain is classified as spam, no indexer will really help you.
Running an indexer on these types of pages can help to restore traffic by a few % but it will continue to be at -99% of the traffic the domain had originally.

Part 3: Extremely obvious Google manipulation
We have seen domains where website owners try to capture every variation possible of a keyword.
It is very obvious to Google (and Google’s quality raters) what you are doing.
Expect to get shadow-banned within a few months.

You don’t have an indexing problem. You have a content problem.
To recover the domain, you have to delete most of the content or rewrite it.
Part 4: No backlinks
The more websites link to you, the more search engines trust your content (directionally).
You can check your backlinks here: https://ahrefs.com/backlink-checker
If you’re domain rating is low or 0 and you have few referring domains, you should build more links.
One of the cheapest ways is to build foundational links.
If you have a domain rating of 0, it is very, very unlikely you will get 400,000 pages indexed.
From thousands of past projects, this is what we have seen:
A DR0 can permanently index 100 quality pages
A DR10 can permanently index 500 quality pages
A DR20 can permanently index 1,000 quality pages
A DR30 can permanently index 10,000 quality pages
A DR50 can permanently index 100,000 quality pages
How to fix real indexing issues
1.) Improve your content
If your content is too short and/or does not have a lot of insights, consider to expand on it. Take the top ranking search results and list all parts of that page.
If it has these sections, you should have them too:
- Table of Contents 
- Introduction 
- Expert Quotes 
- Author section 
- …. 
2.) Fix your meta tags (description/title) and canonicals
Make sure your page has clear and descriptive meta titles, description and a self-referencing canonical. We see that Google can struggle to correctly index large websites without canonicals.
If you have a website with content in different languages, you must use the hreflang.
3.) Build internal links
Make sure that you build internal links to all pages that you want to have indexed. Pages on your website without any internal links are considered “orphan pages” and are less likely to be indexed.
4.) Use an Indexer
Indexers like SEOCopilot are great at helping to index pages that google has “forgotten” to index.
They are not a silver bullet to index terrible pages.
They can help index bad pages for a short while but these pages typically fall out of the index again after 2-3 months.