Web Scraping Best Practices and Tools 2023
There are several tools and libraries available online to build a web scraping application in minutes. Yet, if you want your crawling and scraping process to be reliable, you need to follow some web scraping best practices.
Here, you'll find all the best practices for web scraping you need to know. Follow them and take your web scraping process to the next level!
What is Scraping? And Why Is It Useful?
Web scraping is about extracting data from the Web. Specifically, web scraping refers to the retrieval of data from web pages through an automated script or application. Scraping a web page means downloading its content and extracting the desired data from it. Learn more about what is web scraping in our in-depth guide.
Now, you might be wondering why you need web scraping. First, scraping the Web can save you a lot of time. This is because web scraping allows you to automatically retrieve public data from the Web. Compare this operation with manual copying, and you'll see the difference.
- Competitor analysis: by scraping data from your competitor's websites, you can track their services, pricing, and marketing strategies.
- Market research: you can use web scraping to collect data about a particular market, industry, or niche. For example, this is especially useful when it comes to real estate.
- Machine learning: data scraped can easily become the main source of your machine learning and AI processes.
Let's now see how you can build a reliable web scraper with the most important web scraping best practices.
Top 10 Web Scraping Best Practices
Let's now dig into the ten most important best practices for web scraping.
1. Don't overload the server
Your crawler should never make too many requests to the same server in a short time. That's because your target website may not be able to deal with such a high load. So, be sure to add a pause time after each request.
This delay between requests allows your web crawler to visit pages without affecting the experience of other users. After all, performing too many requests could overload the server. That'd make the target website of your scraping process very slow for all visitors.
Plus, executing many requests may activate anti-scraping systems. These have the power to block your scraper from accessing the site, and you shouldn't overlook them. In other terms, the goal of your web crawler is to visit all pages of interest of a website, not to perform a DoS attack.
Also, consider running the crawler at off-peak times. For example, traffic to the target website is likely to drop significantly at night. That's one of the most popular web scraping best practices.
2. Look for public APIs
Many websites rely on APIs to retrieve data. If you aren't familiar with this concept, an API (Application Programming Interface) is a way for two or more applications to communicate and exchange data.
Most websites retrieve the data needed to render Web pages from APIs in the frontend. Now, let's assume that's what your target site's doing. In this scenario, you can sniff these API calls in the XHR tab of Network section of your browser's development tools. Learn how to intercept HXR requests in Python.
As shown above, here you can see everything you need to replicate those API requests in your scraper. This way, you'll get the data of interest without scraping the website. Also, keep in mind that most APIs are programmable via body or query parameters.
So, you can use these parameters to effortlessly get the desired data in human-readable formats through the API response. Also, these APIs may return URLs and useful information for web crawling.
3. Respect the robots.txt file and follow the sitemap
robots.txt's a text file that search engine crawler bots read to learn how they're supposed to crawl and index the pages of a website. In other words, the robots.txt file generally contains instructions for crawlers.
Thus, your web crawler should take robots.txt into account as well. Typically, you can find the robots.txt file in the root directory of your website. In other words, you can generally access it at https://yourtargetwebsite.com/robots.txt.
This file stores all the rules on how web crawlers should interact with a website. So, you should always take a look at the robots.txt file before starting to crawl your target site. Also, this file can include the path to the sitemap.
The sitemap is a file that contains information about the pages, videos, and other files on a website. This generally stores the set of all canonical URLs that the search engines should index. As a result, following the sitemap can make web crawling very easy. So, thanks to these web scraping best practices, you can save a lot of time.
4. Use common HTTP headers and rotate User-Agent
Anti-scraping technologies examine the HTTP headers to identify malicious users. In detail, if a request doesn't have a set of expected values in some key HTTP headers, the system blocks it. These HTTP headers generally include Referrer, User-Agent, Accept-Language, and Cookie.
Specifically, the User-Agent header contains information that specifies the browser, operating system, and/or vendor version from where the HTTP request comes from. This is one of the most important headers that anti-bot technologies look at. If your scraper doesn't set the User-Agent of a popular browser, its requests are likely to be blocked.
To make your scraper less tractable, you should also keep changing the value of these headers. This is especially true for User-Agent headers. For example, you can randomly extract it from a set of valid User-Agent strings.
5. Hide your IP with proxy services
You should never expose your real IP when performing scraping. This is one of the most basic web scraping best practices. The reason is that you don't want anti-scraping systems to block your real IP.
So, you should make requests through a proxy service. In detail, a proxy server acts as an intermediary between your scraper and your target website. That means that the website server sees the proxy server's IP, not yours.
Keep in mind that premium proxy services also offer IP rotation. This allows your scraper to make requests with ever-changing IPs, making IP banning more difficult. Note that ZenRows offers an excellent premium proxy service.
Learn more on how to rotate proxies in Python.
6. Add randomness to your crawling logic
Some websites rely on advanced anti-scraping techniques based on user behavior analytics. These technologies look for patterns in user behavior to understand whether the user is human or not. The idea behind them is that humans don't follow patterns when navigating a website.
So, you may need to make your web scraper appear human in the eyes of these anti-scraping technologies. You can achieve this by introducing random offset and mouse movements into your web scraping logic, as well as clicking on random links.
7. Watch out for honeypots
Honeypot websites are decoy sites containing false data. Similarly, honeypot traps are also hidden links that legitimate users cannot see in the browser. Honeypot links usually have the CSS display property set to "none" so that users cannot see them.
When the web scraper visits a honeypot website, an anti-scraping system can track it and study its behavior. Then, the protection system can use the collected data to recognize and block your scraper. You can avoid honeypot websites by making sure that the website the scraper is targeting is the real one.
Similarly, the anti-bot system blocks requests from IPs that clicked on honeypot links. In this case, one of the best practices for web scraping is to avoid following hidden links when crawling a website.
8. Cache raw data and write logs
One of the most effective web scraping best practices is to cache all HTTP requests and responses performed by your scraper. For example, you can store this information in a database or log file.
If you download all the HTML pages visited during the crawler process, you can then perform new scraping iterations offline. This is great for extracting data you weren't interested in during the first iteration.
If saving the entire HTML document represents a problem in terms of disk space, consider storing only the most important HTML elements in string format in a database.
Also, you need to know when your scraper has already visited a page. In general, you should always keep track of the scraping process. You can achieve this by logging the pages visited, the time required to scrape a page, the outcome of the data extraction operation, and more.
9. Adopt a CAPTCHA Solving Service
CAPTCHAs are one of the most widely used tools by anti-bot protection systems. In detail, CAPTCHAS are challenges that are easy to solve for a human being, but not for a machine. If a user can't find a solution to the CAPTCHAs, the anti-bot system labels it as a bot.
Popular CDN (Content Delivery Network) services come with built-in antibot systems involving CAPTCHAS. One of the best web scraping practices to bypass CAPTCHAs is to adopt a CAPTCHA solving service.
These farm companies offer automated services to get a pool of human workers to solve CAPTCHAs. Yet, the fastest and cheapest option to avoid CAPTCHAS is to use advanced web scraping APIs that can avoid blocking screens.
Learn more on how you can automate CAPTCHA solving.
10. Avoid legal issues
Before starting to scrape data from a website, you need to be sure that what you want to do is legal. In other words, you must take responsibility for the scraped data. This is why you should take a look at the Terms of Service of the target website. Here, you can learn what you can do with the scraped data.
In most cases, you don't have the right to republish the scraped data somewhere else for copyright reasons. Violating copyright can lead to legal problems for your company, and you want to avoid that.
In general, you must perform web scraping in a responsible way. For example, you should avoid scraping sensitive data. As you can imagine, this is one of the most respectful best practices in scraping data from the web.
What Are the Best Scraping Tools?
The seen web scraping best practices are useful but, to make web scraping easier, you need the right web scraping tool. Let's take a look at some top web scraping tools:
1. ZenRows ZenRows is a next-generation web scraping API that allows you to scrape any website easily and effectively. You can think of ZenRows as a fully-featured web scraping API and data extraction tool.
With ZenRows, you no longer have to worry about anti-scraping or anti-bot. And, for the most popular websites, the HTML is converted into structured data. This makes ZenRows the best web scraping tool on the market.
2. Oxylabs Oxylabs is one of the most popular proxy services available. Proxy servers are the basis of anonymity and allow you to protect your IP. Oxylabs is a market-leading proxy and web scraping solution service. It offers both premium that enterprise-level proxies.
3. Apify Apify is a no-code tool that allows you to extract structured data from any website. Specifically, Apify offers ready-to-use scraping tools that allow you to perform data retrieval processes that you'd typically perform manually in a web browser. Apify is a one-stop shop for web scraping, web automation, and data extraction.
4. Import.io Import.io is a cloud-based platform that allows you to extract, convert, and integrate unstructured and semi-structured data into structured data. You can then integrate into web apps with APIs and webhooks. Import.io offers a point-and-click UI and is specialized in analyzing eCommerce data.
5. Scrapy Scrapy is an open-source and collaborative framework to extract data from the Web. Specifically, Scrapy is a Python framework that provides web scraping API to extract data from online pages via XPath selectors. Scrapy is also a general-purpose web crawler.
Conclusion
Web scraping is a complex science, and you need some rules to follow if you want to build a reliable application. There are several best practices for web scraping, and here you had a look at the most important ones.
- What web scraping is and what it's useful for.
- What tools you should adopt to perform web scraping.
- What the 10 most useful web scraping best practices are.
- What the 5 most important web scraping tools are.
You can spend time and money to implement everything you need to follow all these best web scraping practices. Otherwise, sign up for free on ZenRows and get access to several features based on the mentioned web scraping best practices.
Did you find the content helpful? Spread the word and share it on Twitter, or LinkedIn.