What is a search index and how does it work?

When you use search functionality online or in an application, what happens? How does the search engine take your input and generate relevant results from it? 

Spoiler alert: it’s not magic. It revolves around search engine indexing.

What is a search index, how does it work, and how can using search engine indexing help your business? 

What is a search index?

If you’ve used reference books such as encyclopedias, you’re familiar with the concept of an index. To find information in an encyclopedia, you typically start by flipping to the index in the back, where the topics are organized in alphabetical order with their respective page numbers. 

You may be less familiar with the concept of search indexing. It’s the means by which data is organized and structured so that search engines can generate relevant search results. Search indexing can transform any and all data and file types into searchable data. 

The goal is to make searching as fast, accurate, and relevant as possible. That’s important because most of us use search functionality all day, every day, whether we’re entering search queries on the Google or Microsoft Bing homepage, doing a web search for local restaurants, trying to locate an old friend on Facebook, looking for FAQs or a tutorial about a product issue, searching a CRM for useful content, or trying to track down a document in Dropbox.

So what is a search index?  Basically, a set of structured data examined by a search engine looking for information relevant to a searcher’s query. A search index is tailored to the particular way that the search engine algorithm retrieves information.

How does search indexing work?

Search indexes for websites are generated by web crawlers (also known as web spiders), which collect content from web pages and organize it by keywords. Many search tools also take search intent and semantic meaning into consideration when generating search results. Crawling typically takes place on an ongoing basis so that new content can be covered and the search index is kept up to date in near real time.

Creating a search index is essentially highlighting, signposting, and telling the search functionality what information is on a page or in a file. When it comes to websites, the search index points out the key terms (“keywords”) that indicate what the page is about, what its purpose is, and what content it should be discovered for. This way, every time someone searches for something, the search functionality looks for the information signposts, eliminating a significant amount of the workload. 

In workplace applications, on ecommerce sites, and on news and media websites, search functionality works in a similar way. 

A world without search indexing

We could talk about the benefits of search indexing, but instead, let’s do the opposite: imagine a world without search to understand just how radically search indexing can transform a business’s outlook.

What would a world without search indexing look like? 

In a word, antiquated.

Without good search indexing, Internet search engines would produce search results very differently. You wouldn’t get results in an instant, you’d get them only as they’re found by the crawler. 

This is difficult to imagine because we’re so used to search engines like Google presenting relevant results in milliseconds after Google crawls a ton of content. But search functionality for organizations’ websites doesn’t typically work like it does in a Google search, especially if multiple systems and large databases must be searched. And with legacy systems, there could be problems with integration and accessing siloed information, with some site owners’ data remaining off limits. Therefore, search could be slow. 

So knowing how to optimize search indexing is crucial. You might work for a company that provides an ecommerce or software-as-a-service (SaaS) workplace app or media platform, and you’re looking to provide your customers with better search experiences. Or maybe you’re at an organization that builds custom applications for your customers’ new sites, and the webmasters are also requesting excellent search functionality.

Paying attention to search indexing is likely to pay off. If organizations can’t or won’t improve their search indexing in applications, they may:

Lose customers…and fast

Search is fundamental to the modern online customer experience. People are impatient and fickle; they’re willing to jump ship and try out a competitor’s product if the user experience doesn’t meet their expectations. The longer a search takes, the more customers you stand to lose.

  • According to Google, a 3-second page-load time increases the likelihood of users bouncing by 32% compared with one that takes 1 second. If the page takes 10 seconds to load, the probability of bouncing increases to 123%.
  • Research from Unbounce shows that approximately 70% of people say page-load speed affects whether they buy from an ecommerce site.

See your productivity plummet

As organizations embrace the remote and hybrid workplace model, they’re discovering how important seamless digital experiences are for employee productivity. In addition to moving legacy apps to the Cloud and digitizing key processes, improving enterprise search is crucial. Instituting search indexing across applications and databases can help employees find what they need quickly and efficiently. Without indexing, you’re stuck with the wasted time and frustration that results from slow page loading.

Run afoul of compliance laws

Having excellent search is an important part of staying in line with a wide range of governance and compliance standards for data protection. Whether it’s to comply with the EU’s General Data Protection Regulation (GDPR) or the California Consumer Privacy Act (CCPA) or simply to stay in line with your organization’s internal governance policies, having quick and accurate search is crucial.

When it comes to the GDPR, not being unable to present customer data quickly and easily can result in high fines and damage to your company’s reputation. Good search indexing doesn’t just make search happen fast, it makes what needs to be visible accessible.  

Getting search indexing right

Algolia lets organizations spanning a variety of industries provide effective search in record time, with a solution you can scale as your company grows. Our search API enables the retrieval of files, contact information, events, and more in your app, in your ecommerce marketplace, or on your website. Search indexing is used in the API to power fast, informative, display-ready search results.

So, what is a search index? You now have a grasp of the fundamentals. If you want to know more about this and how improved search experiences can help your organization succeed, contact our team today.

About the authorAdam Smith

Adam Smith

Sr. Director, Digital Marketing

Recommended Articles

Powered by Algolia AI Recommendations

12 ways to improve your search index

12 ways to improve your search index

Jon Silvers

Jon Silvers

Director, Digital Marketing
An Exploration of Search and Indexing: Fast Indexing Scenarios

An Exploration of Search and Indexing: Fast Indexing Scenarios

Peter Villani

Peter Villani

Sr. Tech & Business Writer
The (almost) ultimate guide to site search

The (almost) ultimate guide to site search

Ivana Ivanovic

Ivana Ivanovic

Senior Content Strategist