What is parsing and how does it work?

Often, the necessary data cannot be aggregated manually, or it takes a lot of time. That's where parsing comes in — it's the process of automatically collecting information from websites in a structured format. It helps anyone who deals with data aggregation in any form: online businesses and their representatives, marketers, analysts, and SEO optimizers.

Today, we will break down what parsing is in simple terms, how it works, and which services allow you to perform the data collection task most quickly and efficiently.

How parsing works

From a technical point of view, parsing is a method of extracting data from HTML pages of a website. For better understanding, let's introduce several basic terms.

HTML is a markup language that is the foundation of any page. HTML tags explain to the browser how to display text, where to insert links, and where the image is located. The parser downloads the HTML code to extract the necessary pieces of information from it.

XML is a language for storing and transmitting data between programs. It is in XML format that sites usually upload their products. It is much easier and more convenient to parse the necessary information from it.

JSON is a popular data exchange format that is understandable for both computers and humans. Information in it is stored as key-value pairs, for example, { "name": "Mike", "age": 40 }. Most sites today use JSON when loading products, from which parsers extract the necessary data.

CSS selectors are specific pointers to specific elements of a web page. For example, if you want to find all the headings highlighted in green, you will need the selector h2.green.

XPath is a query language that allows you to navigate the structure of an HTML or XML document like a navigator. You can set tasks for it like "Find the third paragraph inside a table that is located in the right column and take a link from it." It is indispensable in very complex and deep code.

Regular expressions are a tool for finding and extracting text based on a pattern. For example, if you need to parse all phone numbers in the format "+7 (999) 123-45-67", a regular expression will do it instantly.

Now we can list and explain the main stages of parsing:

1. Data retrieval. At the first stage, the parser sends a request and downloads the source material. The source can be a web page (HTML code), a website API (with information being returned in a clean format, for example, in JSON), or a ready-made file (XML or CSV export).
2. Data preprocessing. The downloaded array of data needs to be put in order: unnecessary elements (HTML tags, CSS styles, etc.) that interfere with analysis and do not have value for obtaining the result are removed from the raw text.
3. Structure analysis. The program studies the skeleton of the received document and assesses the hierarchy: where which heading lies, in which block the price is located, and so on.
4. Data extraction. Using navigation tools (XPath, CSS selectors, etc.), the parser selects the necessary data: product names, contacts, prices, or links.
5. Data storage. The collected information is structured on shelves in a convenient format: a simple table (CSV, Excel), a database (SQL), or a flexible file for data exchange (JSON).

Parsing tools: overview of popular solutions

Knowing what parsing is, we can move on to analyzing tools that differ in capabilities, tariffs, and additional options. We will analyze the most popular of them, based on the format of working with content.

Specialized programs

If you need a powerful and functional tool that is installed directly on your computer, you should take a look at specialized programs. They offer wide possibilities for parsing settings, often work through a visual interface (point-and-click), and are suitable for regular data collection from a wide variety of sites: from simple online stores to complex web applications with dynamic content loading.

Octoparse is a popular data parser used to collect information about users, products and services, as well as to conduct various studies. With it, you can parse sites by element type with exporting the results to Excel, CSV, and via API, and without any coding knowledge.

Octoparse has a free version, which has a limit of 10 tasks per month. More advanced plans start at $69 per month, and there is customization of the personal account — in this case, the tariff is set by agreement of the parties.

ParseHub is a web scraping program for automating the collection of information from the Internet. It is actively used by marketers, researchers, analysts, and specialists in the field of e-commerce. Data can be exported in Excel, API, or JSON format.

The free ParseHub tariff includes up to 5 tasks, the data for which is stored for 14 days. The price of the standard version is $189, and the professional tariff with 120 tasks and saving files and images will cost $599 per month.

WebHarvy is specialized software for parsing data with support for multi-page, keywords, and JavaScript. Among its advantages is smart pattern recognition, for which no additional settings are required.

WebHarvy is price-friendly: the basic version of the software for one user will cost $129 per year. And for $699 you can buy a yearly license with an unlimited number of users in the account.

Online services

For those who do not want to overload their computer or need a ready-made infrastructure for large-scale data collection, cloud-based online services are an ideal choice. They take over all the technical troubles from managing proxies and bypassing blocks to providing data through a convenient API. Such platforms allow you to quickly connect to data collection without complex installation and configuration.

Import.io is a site for collecting information on the Internet in real-time. It allows you to extract phone numbers, IP addresses, email addresses, and images with full data analysis. More than 100 web sources are available for simultaneous operation.

Import.io does not have a free or trial version. There are two main tariffs: Fully Managed and Self-Service Solution, and the price for both is calculated individually by the service manager depending on your tasks and needs.

Diffbot is a parsing service for collecting data from websites of organizations, news sites, and product catalogs. It is designed to work with large amounts of information, while customers only have access to the web version in English.

The free version of Diffbot provides quite a lot of opportunities for parsing and is activated without linking a bank card. Paid tariffs start at $299 per month.

Apify is a data collection service that has been operating since 2015. It functions as a simple and accessible web environment using only interface JavaScript. With Apify, you can collect and structure any information from Internet sites with subsequent export to CSV, Excel, or JSON.

Apify has a free version, but it involves paying $0.3 for each new block of calculations. The Starter tariff will cost $29, and the most expensive is Business — $999 per month.

ScraperAPI is a data extraction system from the Internet with flexible solutions for individual users and large companies. A unique advantage of the service is the function of identifying and bypassing bots, due to which almost all of its requests reach the sites and return with a result.

ScraperAPI does not have a completely free version, but you can take advantage of a trial with limited features for a period of 7 days. For personal use or small projects, the minimum Hobby tariff at a price of $49 per month is perfect, more expensive service packages will cost from $149 to $475 per month with a significant expansion of the volume of requests and data storage period.

WebScraper is a parsing program designed to work with big data, including databases, product catalogs, and various lists. It features an intuitive interface and works great with complex sites with multi-level navigation.

In the free version, WebScraper works as a browser extension and with a minimum of working functions, which includes only uploading data to CSV and XLSX. Therefore, it is better to start with the Project tariff at a price of $50 per month: it gives almost all the necessary resources for parsing, you can also get a free weekly trial. The Professional and Scale packages for $100 and from $200 per month, respectively, increase the number of available links, parallel tasks, and the data storage period.

Niche tools

Parsing can be not only general, but also for specific professional tasks. A separate niche is occupied by highly specialized tools tailored to a specific type of data or source. They are not suitable for universal tasks, but they will be useful for working in specific areas.

Screaming Frog SEO Spider is a niche tool for SEO specialists that allows you to audit sites and identify inaccuracies in them. Thus, the software can detect broken pages, title duplicates, pages with missing descriptions, and in general any pages with certain repeating fragments. In the search panel, you can enter not only the entire site, but also a number of selected pages.

The free version of Screaming FROG SEO Spider allows you to parse data in a limited way with a limit of 500 URL links. The paid version opens unlimited opportunities for parsing and crawling, it will cost $279 per year.

Netpeak Spider is an advanced parser for studying web resources and finding errors in them. The service allows you to identify errors in the code, incorrectly configured redirects, content duplicates, and other problems. All the information received can be uploaded in Excel format.

Netpeak Spider has a 14-day trial. Paid solutions start from $20 per month, the most expensive tariff is $99 per month.

Zengram is a service for developing accounts on Instagram with the ability to wind up likes and subscribers. Of particular interest to us is its parser, with which you can collect accounts on this social network by hashtags, geolocation, subscribers, and subscriptions. Data can be exported in .txt format.

Zengram provides full access to the service for 3 days to each new user. Further, there are two tariffs at a price of $35 and $60: the more expensive one differs in the guarantee against blocking and an improved parsing algorithm.

Scrapingdog is a parsing program with the ability to solve a variety of tasks, but most often it is used to collect data from the social network LinkedIn. The service allows you to collect profiles of companies and users according to selected criteria and exports data in JSON format.

You can use Scrapingdog for free for 30 days. Then you will need to subscribe to the service: this is at least $90 per month, as a maximum at Business tariff is $500 per month.

Conclusion

Parsing is an indispensable step in the process of making money on the Internet for specialists from many online spheres. With parsing, you can quickly collect data that is publicly available. There are many services on the network that provide parsing services on a broad topic or with a specific specificity, so choose the one that best solves your tasks and get to work. And in the following articles, we will delve into the topic of parsing and tell you more about this technology and the services that allow it to be implemented.