Bypassing PerimeterX For Web Scraping

Web scraping, the process of using automation tools to crawl through websites and extract data from them, has become more prevalent in recent times. It is versatile, as it aids research and decision-making in various industries. Web scrapers face many challenges as many websites have increased the barriers and measures to detect and mitigate web scraping activities.

One such barrier is to bypass PerimeterX, a popular anti-bot technology. PerimeterX is a top provider of solutions that safeguard internet platforms from bot attacks. This article will explain PerimeterX, how it hinders web scraping, and how to overcome it, including ZenRows as an easy solution.

How Does PerimeterX Work?

When you visit a website, it collates some data, including your device and browser information, the IP address to show your location and internet service provider (ISP), cookies, etc.

If PerimeterX is already engaged on a website, when you load that site, it includes a JavaScript security loader code in the HTML document you are downloading. It is programmed to run some tests in the browser to detect abnormal behaviours. It inspects the user input behaviour, the amount of time spent between web activities, cookies, browser history, IP address, etc.

PerimeterX has trained machine learning (ML) models to establish what is accepted as normal behaviour. The results of these tests are sent to PerimeterX, which processes the data. It compares the results to what is regarded as normal behaviour.


The closeness of these results to the acceptable metric determines the security score. If the result is close to the acceptable security score, the browser will be allowed to access the site, although monitoring will still happen while the user is on the site.

The browser-specific object has to match the browser name or it will be flagged as an anomaly. Also, PerimeterX can analyze the “localStorage” object. If it detects unusual or excess storage activities, it notes it as an anomaly. PerimeterX will then deploy detection mechanisms when abnormal activities are spotted.

Common Techniques PerimeterX Uses

  1. Rate Limiting: Rate limiting refers to imposing a maximum number of API calls or requests a single user can make within a period. If the number of requests from your web scraping tool exceeds the rate limit, it will be throttled.
  2. Browser Behaviour: Automated bots will most likely perform activities on the web faster than humans. PerimeterX employed advanced behavioural analysis to monitor how you (or your web scraping tools) interact with the site. By checking the click patterns, session duration, and mouse movements, PerimeterX can tell whether it is a human or a bot on the website.
  3. Human Challenges: PerimeterX also implements challenges that require human intelligence to complete. Some of these challenges include puzzles or simple questions.

Bypassing PerimeterX Challenges

As PerimeterX (and bot detection measures generally) become more popular, technologies and strategies are created to bypass or overcome its challenges. See some of them outlined below.

1. Headless Browsers:

A headless browser is like a regular web browser, but with one unique characteristic: it does not have a graphical user interface (GUI). A GUI is a user interface with visual elements that help users to communicate with a computer. It includes buttons, icons, checkboxes, URL bars, menu bars, etc. Headless browsers lack all of these and hence do not have graphical rendering.

With headless browsers, it's easier to customize user agents. When you edit the user agent to match real browsers, it becomes harder for PerimeterX to tell you apart from real users if done properly. Hence, the likelihood of it detecting your web scraping activities is lower.

2. Proxy Servers:

A proxy server serves as a middleman between the user and the destination server. In this case, when you make requests, they are first sent to the proxy server before the final server. Proxy servers hide the true IP address of a user.

When using rotating proxies, you can change your IP address periodically or route your requests through different browsers. By doing so, PerimeterX cannot attribute your speed or activity volume to one user (because they are from different locations). Hence, you are less likely to fall way below the security score and trigger anti-bot techniques.

3. Web Scraping APIs:

A web scraping API is a software intermediary that simplifies the process of web scraping. It enables the automated extraction of data from websites and delivers the content of the page.

It handles all the behind-the-scenes complexities involved in web scraping, such as JavaScript execution, proxy rotation, parsing HTML, etc. It simulates the actions of a human user throughout web scraping processes, such as waiting for the page to load, making it harder for PerimeterX to detect bot actions.

ZenRows is the leading web scraping API that manages all techniques to bypass anti-bot detection measures, including headless browsers, CAPTCHAs, rotating proxies, and many more. It comes with a suite of features that can help you overcome the challenges to bypass PerimeterX seamlessly and at affordable pricing.


By now, you must have learnt about what web scraping entails and the challenges of web scraping. You also read about what PerimeterX does, how it works, and how to bypass it.

Asides from the ones mentioned in this article, there are other strategies for overcoming PerimeterX. However, using web scraping APIs is the most reliable option. An excellent web scraping API to use is ZenRows.

ZenRows is easy to set up and integrate, reliable, and scalable. It is an effective way to bypass PerimeterX challenges. To get started, head on to the official website.

In case you have found a mistake in the text, please send a message to the author by selecting the mistake and pressing Ctrl-Enter.

Comments (0)

    No comments yet

You must be logged in to comment.

Sign In / Sign Up