What is website parsing and why is it needed?

Site parsing is a process of automatically collecting information from web pages, which allows you to get the necessary data in a structured form. It is widely used to analyze large volumes of information that can be used for various purposes: from monitoring product prices to collecting contacts of potential customers or market analysis.

The basic idea of ​​parsing is to collect certain elements from pages (text, images, tables or metadata) and save them in a convenient format, for example CSV or JSON. This helps businesses to quickly obtain relevant data for decision-making, conduct competitive analysis, monitor trends, and automate processes, which significantly reduces time and resource costs. Parsing is often used in e-commerce to compare product prices, in research — to gather information from news sites, and in SEO — to analyze competitor content.

And all this is possible thanks to the parser. It is not a single person, a parser is a program or script that automatically analyzes and processes data from various sources, such as websites or files.

The main task of a parser is to extract the necessary information from unstructured data and transform it into a structured form that is convenient for further use. A parser works by analyzing code or text, breaking it into components and extracting the required elements, such as prices, titles, descriptions, etc.

In this article, we will take a detailed look at the topic of parsing, what are the methods, how to protect your site, and is it even legal in Ukraine?

When is parsing needed?

Let’s start with when it is relevant to use parsing. There are two main reasons for this.

1. Optimization of own web resource through data analysis

Parsing can help analyze your site in detail, identify technical issues, optimize content, page structure, and improve SEO. This allows you to get information about performance errors, page loading speed, keywords you use and the positioning of your site in search engines.

2. Strategic business growth with the help of parsing

Parsing can be a powerful tool to grow your business through access to useful data. Below are a few ways this can help.

2.1. Analysis of competitors and market dynamics

Collecting information from competitors’ websites allows you to understand their strategies, prices, assortment, as well as to see the dynamics of changes in the market. This allows you to adapt your strategy and stay one step ahead.

2.2. Monitoring reviews and comments

Parsing reviews of competitors’ products or services allows you to understand what customers appreciate or, on the contrary, criticize. This information will help you improve your product or service.

2.3. Filling automation online store

Collecting and adapting information from other sources, for example, foreign online stores, will help to quickly fill your product catalog. This saves time on creating descriptions, images and specifications.

2.4. Formation of a database of potential customers (leads)

With the help of parsing, you can collect contact data of potential customers or partners. This is especially useful for the B2B segment or selling services, where it is important to have a base of contacts for further communication.

Advantages and disadvantages of parsing

It seems that there are only advantages to using parsing, but there are also disadvantages. Let’s consider the pros and cons in more detail.

Advantages of site parsing

1. Speed ​​and scale of data acquisition
   Parsing sites allows you to quickly collect a large amount of data from various sources. This significantly saves time and resources compared to traditional data collection methods such as surveys, interviews or report analysis.
2. Effective marketing and customer monitoring
   Through parsing, companies can track how marketing campaigns work, how consumers interact with products, and analyze reviews and comments. This contributes to a better understanding of customer sentiments and allows you to adjust promotion strategies.
3. Accurate price analysis
   Parsing is often used to monitor competitors’ prices, enabling companies to effectively manage the prices of their own products or services. It also helps to form comparison services for consumers, for example, on platforms such as Amazon or Google Shopping.
4. Targeted lead generation
   Parsing data from B2B sources, such as industry websites or directories, helps you find potential customers. This simplifies the lead generation process and allows companies to better segment target audience.
5. Automation of content creation
   Parsing can be used to aggregate data from different sources and create content. This makes it easier to run informational or news sites, but it is important to adhere to ethical standards and not violate copyright or privacy.

Disadvantages of site parsing

1. Legal restrictions
   Many sites prohibit parsing in their terms of use. Violation of these rules will lead to legal consequences or blocking access to the site.
2. Risk of copyright infringement
   Improper use of collected information may expose the company to claims of copyright or privacy infringement, resulting in reputational damage.
3. Outdated or inaccurate data
   If the site is updated frequently, the parser may provide outdated or inaccurate data. This is especially critical for areas such as pricing or market analysis, where the accuracy of information is of great importance.
4. High technical requirements
   Setting up the parser requires considerable technical knowledge. Processing large amounts of data requires resources for storing and analyzing information.
5. Blocking by sites
   Some sites use security measures such as CAPTCHA or IP blocking. This can complicate or even completely block the data collection process.

What can competitors learn about you using a parser?

Competitors can gain a significant amount of valuable information about your business through parsing. They can easily learn your prices, which will allow them to compare their offers with yours and adjust their own pricing policy to attract customers.

Parsing product cards with descriptions will help them understand your range, key product features and the strengths of your offering.

By analyzing your blog, competitors can gain information about your strategic directions, educational and marketing approaches, which will give them the opportunity to adapt their strategies or use your ideas for their own promotion.

Competitors can parse your contact details to analyze who you do business with and even try to intercept your customers or suppliers.

Parsing feedback will help them learn about your strengths and weaknesses from the customer’s perspective, giving them additional tools to improve their products or services and capture the market.

Data parsing algorithm

This process can be done manually, but it takes a lot of time and effort, so specialized software is usually used – a parser.

The process consists of three main stages:

1. Access to the site
   The parser sends an HTTP GET request to the website that is the source of the data. This is a standard request to the server that returns an HTML page to be displayed on the user’s screen.
2. HTML code parsing
   After receiving the response from the server, the parser analyzes the HTML code of the page. It looks for the right data patterns — these could be specific HTML tags, classes, or attributes that contain useful information like prices, product descriptions, reviews, and more.
3. Extracting and saving data
   After parsing the HTML code, the parser extracts the necessary data and converts it into a convenient format (for example, a table or database) for further use.

There are various data parsing techniques, let’s consider the main ones:

1. Parsing HTML. Using tools or libraries such as Beautiful Soup or Scrapy (in Python) allows you to parse the HTML code of a page and extract data using specific HTML tags or attributes.
2. DOM (Document Object Model) parsing. DOM is a structured model of a web page that represents its elements in the form of a tree. Parsers use the DOM to examine the structure of a site and determine which elements to extract data from.
3. XPath is a special query language for navigating and selecting elements from XML or HTML documents. XPath is often used in conjunction with Beautiful Soup or DOM to more precisely highlight the data you want.
4. Access via API. Some sites provide official APIs to access their data. This method is considered more ethical and controlled because APIs provide secure and authorized access to information.
5. Vertical aggregation. Large companies with sufficient capacity can use cloud platforms to collect data from certain industries. Vertical aggregation allows large volumes of data to be re-collected over a period of time from multiple sources.
6. Google Sheets is a simple method for collecting data. Google Sheets has an IMPORTXML feature that allows you to extract data from sites. This feature can also help check if a site is protected from parsing.

The process looks quite simple, but in reality it is difficult to implement due to various factors, such as protecting websites from bots, changing the structure of the HTML code, complex algorithms for finding the necessary data. Therefore, it is important to choose the right parser and methods for efficient parsing.

Is it legal to parse websites in Ukraine?

In Ukraine, the parsing of sites is not subject to legal restrictions, because the Constitution of Ukraine guarantees the right to free access to information. In particular, Article 34 of the Constitution notes that everyone has the right to freely collect, store, use and disseminate information in any way.

Law of Ukraine “On access to public information” confirms this right by allowing free access and use of information, unless the law establishes special restrictions. However, there are important exceptions to consider.

Parsing of personally identifiable information is limited. In order to collect such data, permission must be obtained from the site owner or information manager. De-personalized data that does not allow the identification of an individual can be parsed without restrictions, unless there are other legal prohibitions. It is important to check whether the information is confidential in accordance with the privacy policy stated on the site.

Parsing that is prohibited:

1. Violation of the law by creating an excessive load on the server or other forms of attack.
2. Searching and collecting personal information that is not publicly available without users’ permission.
3. Posting articles, photos, videos and other content under your name without the permission of the owners.
4. Collection and distribution of information that is a commercial or state secret.

According to the Law of Ukraine “About copyright and related rights”, you need to be careful about possible copyright violations. Authors of materials have the right to determine the terms of their use. Therefore, it is important to follow privacy and copyright rules when parsing sites to avoid legal consequences.

How to protect your web resource from parsing?

To effectively protect your site from parsing, you can apply several methods that will help prevent unauthorized data collection and guarantee the safety of your information.

1. Limiting the number of requests
   One of the first steps is to limit the number of requests that can be sent from a single IP address. Setting rate limiting will help reduce the load on the server and make it difficult for bots to continuously access data. This can be implemented using server settings or special request control tools.
2. Using API with rate limiting
   Implementing an API that has request rate limits and usage policies allows you to control access to the content of your resource. The data will be used only for legal purposes.
3. Implementation of CAPTCHA
   Adding CAPTCHAs to forms on your site will help make it harder for automatic access to your data. CAPTCHA requires users to perform tasks that are difficult to automate, thus weeding out bots.
4. Dynamic web content
   Using dynamic web content that is generated server-side will help slow down or stop bots as they have difficulty interpreting complex scripts and JavaScript.
5. Placing TOS and robots.txt documents.
   Your site should have a Terms of Service (TOS) document that specifically limits and prohibits data collection and the use of bots. Document robots.txt should also contain clear instructions for web parsers, specifying which parts of your site can be indexed and collected.
6. Identification and blocking of bots
   Using a system to detect bots, which can recognize automated requests based on behavioral patterns, allows you to block or limit access to the site for unwanted users.

These practices will help protect your site from unauthorized data collection, reduce risk, and provide greater control over access to your information.

Serhii Ivanchenko

CEO

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