Web Scraping Glossary
A
Anti-Bot System
Software designed to detect and block automated access to websites. Common examples include Cloudflare, Akamai Bot Manager, DataDome, and PerimeterX. These systems analyze browser fingerprints, mouse movements, and request patterns to distinguish bots from humans.
API (Application Programming Interface)
A set of protocols and tools for building software applications. In web scraping, APIs allow programmatic access to data without parsing HTML, often providing structured JSON or XML responses.
B
Bot Detection
The process of identifying automated web traffic. Techniques include CAPTCHAs, JavaScript challenges, behavioral analysis, and TLS fingerprinting.
Browser Fingerprinting
A technique used to identify unique browsers by collecting attributes like screen resolution, installed plugins, canvas rendering, WebGL capabilities, and timezone. Anti-bot systems use this to detect scrapers.
C
CAPTCHA
Completely Automated Public Turing test to tell Computers and Humans Apart. A challenge-response system used to determine whether a user is human. Types include image recognition, text-based, and invisible CAPTCHAs.
Crawl Rate
The speed at which a web scraper or search engine bot requests pages from a website. Managing crawl rate is essential to avoid overloading servers or triggering anti-bot systems.
CSS Selector
A pattern used to select and extract specific HTML elements from a webpage. Common selectors include class names (.class), IDs (#id), and element types (div, span).
D
Data Extraction
The process of retrieving structured data from websites, databases, or documents. In web scraping, this involves parsing HTML/JSON to pull specific data fields like prices, names, and descriptions.
Dynamic Content
Web content loaded via JavaScript after the initial page load. Extracting dynamic content requires headless browsers or browser automation tools that can execute JavaScript and wait for content to render.
E
ETL (Extract, Transform, Load)
A data integration process where data is extracted from sources, transformed into a suitable format, and loaded into a destination system. Web scraping is the "Extract" phase of an ETL pipeline.
H
Headless Browser
A web browser without a graphical user interface, used for automated page loading and JavaScript rendering. Popular headless browsers include Puppeteer (Chromium), Playwright, and Selenium WebDriver.
HTML Parsing
The process of analyzing HTML documents to extract specific elements and data. Parsers like BeautifulSoup, Cheerio, and lxml convert raw HTML into navigable tree structures.
J
JSON (JavaScript Object Notation)
A lightweight data format commonly used for data exchange between web servers and clients. Many modern websites use JSON-based APIs, and scraped data is often delivered in JSON format.
P
Proxy
An intermediary server that routes web requests on behalf of the scraper, masking the original IP address. Types include datacenter proxies, residential proxies, and mobile proxies.
Proxy Rotation
Automatically cycling through multiple proxy IP addresses to distribute requests and avoid detection or blocking by target websites.
R
Rate Limiting
A technique used by websites to restrict the number of requests from a single source within a given time period. Exceeding rate limits typically results in temporary or permanent blocking.
Robots.txt
A text file placed at the root of a website that provides instructions to web crawlers about which pages they can or cannot access. Following robots.txt is considered ethical scraping practice.
S
Scraping
See Web Scraping.
Selector
A pattern used to identify specific elements within an HTML document. The two main types are CSS selectors and XPath expressions.
Structured Data
Data organized in a predefined format (like JSON, CSV, or database tables) that is easily searchable and analyzable, as opposed to unstructured data like raw HTML.
W
Web Crawling
The process of systematically browsing the web by following links to discover and index pages. Unlike scraping (which extracts data), crawling focuses on discovering URLs and page structures.
Web Scraping
The automated process of extracting data from websites. This involves sending HTTP requests, parsing HTML or JSON responses, and storing the extracted data in a structured format.
X
XPath
A query language for selecting nodes from XML/HTML documents. XPath expressions are commonly used in web scraping to target specific elements by their position in the document tree.