Used well, web scraping is a life saver. It allows you to collect the data you need, parse it in a reusable way. We know how important it is for you to have accurate and up to date data. Since we've started scraping the web, we've learned a lot of dos and dont. In this article, we share with you our tips to make the best use of web scraping.
#1 Respect the website and its users
Our first advice is quite a common one: respect the site you're scraping. Read the robots.txt file written by the website's owner to know what pages you can or cannot scrape. In some cases, it will also include information about at what frequency you're allowed to scrape the site.
Also, you should respect the other users visiting the site. Intensive scraping of a website can use a big part of its bandwidth. This will result in other users having a poor experience of the website.
This is web scraping curtesy. If you don't respect those rules, you might end up having your IP address blocked. We will detail this later in the article.
#2 Simulate human behaviour
One of the first goals of web scraping is to collect data faster than if done manually. However, we strongly advise you to scrape slowly. The browsing speed is a great indicator for a website to identify if a user is a person or a scraping bot. If not specified otherwise, a bot will always take the fastest route, making it easy to unmask. This is why we recommend you to add some random delays when you crawl and scrape a website for your bot to be human-like. You can also add random house movements and clicks.
#3 Detect when you've been blocked
Most websites don't appreciate being scraped. Some of them have developed anti scraping methods and will block you. Generally, you will know straight away that you have been blocked, as you will get a 403 error code. However, there is more malicious ways to block you without knowing it. Some websites will still send you some data, but it will be voluntarily fake. By recording logs, you can keep track of how the website responded, and get alerted when anything is unusual: for example, a really short response time.
#4 Avoid being blocked again
When a regular user visits a website, the website will read this person's user agent. It is composed of different details on how this person is visiting their site: what browser, which version, what device he's visiting the page from, etc. Visitors without user agent are automatically labeled as bots. This is why a good trick is to write few different user agents, and regularly rotate between them. You should also be careful of not using old or obsolete browser versions, as this might become suspicious. Update your user agents pool from time to time.
#5 Use Headless Browser
#6 Use the correct proxies and tools
The first thing anti scraping systems will do is to look at your IP address. If you are detected, you'll end up on their IP blacklist and won't be able to visit nor scrape that site again. By using a proxy, your request will appear as if it was coming from a different IP address than yours. Standard proxy provide data center IP addresses. Those are easier to detect and block. By using premium proxies like Zyte, Netnut or SquidProxies, you will get residential proxies, allowing you to bypass any geographical restrictions, and scrape more complicated websites such as Google and Amazon.
#7 Build a Web Crawler
Web crawlers are a great tool to associate with a web scraping API. The crawler will feed to the scraping API the URLs to collect data from. It will update the list of URLs to crawl and scrape as it goes. You can also set some rules to sort which URLs to scrape or not. You can read our article about how to build a web crawler to learn more.
That's it for our main web scraping tips. Most of these are handled by ScrapingBot, so you have nothing to worry about.