Web Crawling vs. Web Scraping; What is the difference?
It’s easy to confuse web crawling and web scraping – they’re both tools’ businesses use to improve information and data gathered from the internet. The two terms are used extensively in the web data extraction industry, with some people using them interchangeably. Web crawling and web scraping are completely different things but both scour through the internet to get you actionable data. I’ll break the two terms down and provide a clear example of each in practice.
The current information age we live in necessitates getting as much information from the internet as possible, without wasting too much time to get and analyse it. Put in simple terms, web scraping collects information from websites – it involves grabbing everything off a web page and compiling it onto something you can analyse. You can review other articles on the site for more details around the frequency of which you should web scrape, and the usual costs of a project.
A web crawl is the process of searching through search engines and websites across the internet for sites that are relevant to what you’re looking for – as done by focusing on keywords and types of data. Crawling refers to scouring through the internet and finding URLs only – ones that fit your search criteria – and bookmarks them or compiles a list for you to review later. It is essentially doing what you could do, but faster and in a wider search than if you were scouring the internet yourself.
These tools work well but also work well together, because they can get precious information needed for many business projects. While there are free-to-try applications out there to try these tools out, it is recommended to seek a professional to get a consultation of the proper steps to incorporate a web crawl or scrape to your next project.
The short answer: Web scraping gathers data from individual web pages, while web crawling searches the internet for relevant websites and collects their URLs for later review. Scraping is focused on specific pages, while crawling is a broader, faster search for websites matching your criteria.
How do you web crawl or scrape?
Each tool can be done in person or using a project-friendly app which can use a program or “bot” to automate the process. Using an app is great if a project has a tighter budget or if trying out the process of web crawling for the first time. The automated approach can provide fast results but less nuance that a person can provide. A technician that specializes in web crawling can better scrutinize data and websites to match what a project needs though it may cost a bit more.
Web scraping is similar in that you can automate the process or get a professional to assist you with similar pros and cons. An app can compile data gathered from a website quickly but cannot sort or discern what is ideal for the project as well as a professional can.
Since both techniques can be automated through an app, or program – a bot – it is easy to understand how the two can be confused for each other. One way to remember each is to visualize what each term does – scraping is to take all the surface information you can grab from a website like a window. A crawl is like slowly crawling through the big internet grabbing at everything that is relevant to you.
Where is crawling used?
Web crawling is used in any industry that has a prominent online presence, but here are a few examples. E-commerce, travel and hotel businesses, real estate, and some social media outlets have been using web crawling for years. Any industry that wants to scour the internet for the most recent, relevant topic.
Alternative uses for web crawling can involve how the process works, by reviewing your own web page. If you scan your own site with a crawler at regular intervals, you can prevent dead end links, or errors that can pop up from using older code or programs. You can also use crawling as a way to see how relevant or “fresh” your website is compared to competitors – if you see your site has gained or lost that “relevant freshness”.
Similar to a site’s RSS feed, you can crawl in real-time to learn if new information is posted on any website you’ve indexed in a previous crawl. Meaning you could crawl to find out if a blog recently made a post, a price has changed on a particular item, or if a site has left an opportunity open for you to take advantage of.
What are each tool used for?
To better explain how both web scraping and crawling work, let’s use a relatable example. A new retail clothing business plans to open up in a new city – let’s say New York City, US – and wants to make a strong online presence. The business focuses on women’s clothes but the owner doesn’t know how many other stores exist in New York City , what the demographic is or what is trending locally.
In this example, the owner wants to web crawl online for other clothing stores within her city to see how many stores there are in New York City before they can get any scraping started.
The owner wants to look up: New York City, US, clothing, women, retail, trend/s, and keywords to their style or cultural influences to their line. The crawling process gives the owner a list of dozens of websites that touch one or more of these keywords and they can now visit these URLs for further study.
That is what web crawling ultimately accomplishes, creating a list of sites that are relevant to what you’re looking for. Crawling may look at a site’s code, but it doesn’t take anything other than copy the URL and add it to a list.
With this list of websites, the owner determines they need to scrape these sites for information on trends, popular items and the demographics that are frequenting these pages. In this example, the owner of a new retail fashion business will have a better debut in New York City, by adjusting their web storefront and their fashion line to the local tastes.
Possible additional steps the business owner can do is to web crawl their own site periodically to make sure their fashion and designs are up-to-date and fresh enough to get new visitors to their site.
They sound a little similar
Since web crawlers can check a site’s relevancy to your keywords – for example how trendy or “fresh” it could be – it can overlap with how a web scraping grabs and collects all data from a website. The key is in the specifics, where a crawl checks imminent relevance and importance based on your search, and a scrape just takes any to all data you plan to examine. Web crawling only indexes – in order of your preference of relevance, fresh success or if a site represents a competitor – and ultimately gives you a list of sites you think is important.
Both web crawling and scraping are versatile tools to keep ahead of information and data online. It’s advised that while free options are available online for each tool, seeking a professional can provide better insight on if and how either should be used, but to help organize how a web project should go. They can tell how to narrow your search for a crawl, and find exactly the information you need, and how frequently you should crawl or scrape.
These tools can vastly improve your next online project, and I recommend you give each a try to improve your online business presence.,