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What Are Bots and How Do They Work on the Web? An In-Depth Guide

Bots have become ubiquitous inhabitants of today‘s internet. As an expert in web scraping and data extraction, I‘ve witnessed firsthand the rapid evolution of bots over the past decade. In this comprehensive guide, we‘ll explore what bots are, how they operate on the web, evasion techniques and the ongoing "arms race" between bot creators and websites trying to block them.

What Are Bots?

Bots are automated programs designed to carry out repetitive tasks online much faster than humans can. They are powered by scripts, algorithms and in advanced cases, artificial intelligence. According to leading bot expert Dhiraj Rajput, "Bots can run 24/7 and handle massive volumes of data and processes far quicker than manual human efforts."

While the modern internet is swarming with bots, they predate the web itself. One of the earliest bots was ELIZA, created in 1964 by MIT professor Joseph Weizenbaum. ELIZA simulated a Rogerian psychotherapist and could convincingly chat with humans by detecting keywords.

With the advent of the web in the 1990s, companies quickly recognized the potential of bots for automating business processes. In 1994, one of the first web crawler bots called World Wide Web Wanderer was created to systematically index the early web. Meanwhile, Excite introduced a chatbot named Clara in 1997 to interact with site visitors.

Today, analysts estimate over 50% of internet traffic comes from bots performing various automated tasks for businesses, researchers, governments and hackers. Let‘s explore some major categories of modern bots roaming the wild web:

Web Crawlers

Also known as spiders, web crawlers are used extensively by search engines like Google to discover and index web pages. Google‘s crawler is called Googlebot. Baidu‘s crawler is Baiduspider. Every major search engine has crawler bots that "crawl" across websites following links.

Crawlers parse page HTML, execute JavaScript, interpret page metadata and more to understand the content. This feeds the search engine algorithm to return relevant results for user queries.

Here are some key stats on search engine crawlers:

  • Googlebot requests over 20 billion pages per day as of 2022
  • Bingbot has crawled over 50 billion web pages
  • Crawlers index the content of over 50 trillion individual URLs

Web crawler bot


Chatbots are programmed to understand natural language queries and respond through textual or voice-based conversations. They use techniques like scripts, natural language processing (NLP) and machine learning to interpret user inputs.

Leading companies employ chatbots to handle customer support inquiries efficiently. According to Juniper Research, the global number of chatbot interactions will rise from 2.6 billion in 2019 to 22 billion by 2023.

Here are some common examples of conversational bots:

  • Restaurant chatbots taking food orders
  • Customer service bots answering questions
  • Shopping bots providing product recommendations

Web Scraping Bots

Web scraping bots programmatically extract specific information from websites and databases. For instance, a bot could scrape product listings from an e-commerce site, real estate data from listings sites or weather reports from meteorological sources.

Scraping bots can be used for market research, monitoring prices, academic studies, journalism and other legitimate purposes given they respect site terms of service.

By automating data extraction, scraping bots save companies massive amounts of time and manual effort compared to humans performing the same tasks. Our clients at Oxylabs often use scraping bots to power business analytics and core processes.

Spam Bots

On the flip side, spam bots aim to harvest data like emails from websites to send unsolicited bulk messages. Email inboxes are frequent targets of spam bots. Bots account for over 90% of global spam volume as of 2022.

Other malicious bots engage in fraud, account takeover attempts or spreading malware. For instance, the MyKings botnet involved over 500,000 bots performing denial-of-service attacks and spreading banking trojans.

Monitoring Bots

Businesses employ monitoring bots to continually check the status of websites, APIs and applications. They verify uptime, performance metrics and catch errors. Monitoring bots can send alerts when issues are detected to enable quick resolutions.

Types of Bots by Function

Bot TypeFunctionExample Use Cases
Web crawlerIndex web pages to power search enginesGooglebot, Bingbot
ChatbotConversational agent for customer engagementRestaurant ordering bot
Web scraping botExtract data from websitesCompetitor price monitoring
SpambotSpread unsolicited bulk messagesPhishing emails, fraud
Monitoring botCheck health of sites and APIsPerformance tracking

This table summarizes some common functional categories of bots roaming the internet along with examples. The use cases are extremely diverse, from powering search engines to spreading malware. Next, we‘ll explore more technical bot classifications.

Rule-Based Bots vs. Intelligent Bots

Bots can also be categorized based on their underlying programming:

Rule-based bots execute predefined scripts and responses. They have limited ability to handle new situations outside their programming. Many chatbots use rule-based conversations powered by keywords and scripts.

Intelligent bots leverage AI and machine learning to continually improve their functioning based on past experience without human intervention. They can adapt to novel inputs. Google and Microsoft chatbots are examples of intelligence-driven conversational bots.

Rule-based vs intelligent bots

How Do Bots Technically Operate on the Web?

Bots are automated programs – they do not function like humans browsing the web with a mouse or tapping on mobile apps. Here are some key ways bots technically operate:

  • Bots programmatically send HTTP requests to web servers to interact with sites and APIs. Requests might fetch a web page, submit data, trigger an action etc.
  • Bots parse through response data like HTML, JSON, images etc. to extract the information needed for their task, whether indexing content or scraping prices.
  • Many bots execute JavaScript to fully render pages and extract dynamic data. But bots do not interpret visual information.
  • Headless browsers like Puppeteer and Playwright allow bots to parse pages and content like a normal browser would. But headless browsers are detectable.
  • Proxies mask a bot‘s real IP address so it can programmatically send requests without getting blocked at the source. Rotating proxies are essential for effective bot operation.

As a proxy expert, I leverage thousands of proxies in rotation when creating resilient bots for web scraping and data extraction. By frequently switching proxies and mimicking organic behaviors, advanced bots can bypass many basic anti-bot measures.

Evolving Cat and Mouse Game: Bots vs Anti-Bot Detection

Websites have strong incentives to detect and block malicious bots like spambots. But often their blanket anti-bot measures also end up hampering beneficial bots used for web scraping. This has given rise to an ongoing "cat and mouse game" between bot creators and site owners.

Some common methods sites use to detect bots:

  • Browser fingerprinting – Headless browsers used by bots lack human attributes like cookies and browser version. Fingerprinting identifies those missing elements.
  • CAPTCHAs – Challenge-response tests aim to deter bots, but machine learning has made many CAPTCHAs solvable by advanced bots.
  • Traffic pattern analysis – Unusual volume, timing and repetition of requests can signal bots over human visitors.
  • IP blacklists – Blocking IPs associated with past bot activity, but rotating proxies help bots avoid this detection.

In response, legit scraping bots aim to mimic human browsing patterns as much as possible:

  • Use proxies – Rotating IP proxies is essential for bots to mask their digital footprint. No two requests come from the same source.
  • Limit request rates– Capping requests per second avoids tripping rate limits. Human delays between requests are added.
  • Browser simulation – Bots can fake mouse movements, scrolling, clicks etc. to appear more human-like to site trackers.
  • Text generation – For chatbots, generating human-sounding text responses helps avoid scripted responses being flagged.

This excerpt from a 2020 ZDNet article summarizes the ongoing battle:

“The very nature of the web and the continuous advancement of technology will only make bots more prolific, which will then put more pressure on detection systems and make anti-bot services tighten their grip. This cyclical sequence of events creates an endless cat-and-mouse game between bot operators and defenders.”

In my experience, staying on the cutting edge of bot evasion tactics as an ethical web scraper involves continually testing new proxy sources, keeping scraping behaviors human-like and leveraging machine learning to capitalize on patterns in anti-bot systems.

Proxy Services Crucial for Bot Operation

As a veteran proxy user, reliable proxy sources are by far the most important factor in creating resilient, stealthy bots for web scraping and automation.

Here are some top proxy providers I‘ve used extensively over the past 5-10 years for bot projects:

BrightData – Over 100 million residential and mobile proxies across 195 locations. Highly reliable with real-time monitoring.

Smartproxy – 40+ million proxies with accurate geo-targeting. Rotating proxies help avoid blocks.

Soax – Residential proxy network in 130 geos. Machine learning algorithms customize proxy behavior.

Proxy-Cheap – Affordable proxy packages. Support for persistent sessions and sticky IPs.

Proxy-Seller – Residential proxies in fixed metro locations ideal for local data gathering.

The scrapers I create leverage thousands of proxies rotating randomly to mask the bot‘s footprint. This is far more robust than using a single static IP. By constantly switching proxy identities, the bot traffic appears highly distributed, avoiding pattern detection.

I‘ve found residential proxies to be the most effective since they come from real devices like tablets, mobile phones and home PCs. This makes them challenging to differentiate from human users compared to data center proxies.

Bots have clearly become a dominant force on the modern internet. Key trends include:

  • Search engine bots crawling 50 trillion+ pages to improve results. Chatbots handling billions of customer interactions.
  • Over 50% of internet traffic estimated to come from bots rather than humans.
  • Malicious bots like spambots unfortunately comprise a significant portion of bot activity online.
  • An ongoing cat and mouse game between bot creators and anti-bot systems as detection methods grow more advanced.
  • Residential proxies on rotating schedules are essential investments for resilient bots that can evade basic protections.

Looking ahead, bots leveraging artificial intelligence and machine learning are poised to become even harder for websites to detect. The economic incentives for bots are only growing stronger with their ability to automate business processes.

Balancing productivity with security will continue as an inherent tension as bot adoption increases. But ultimately, I believe ethical bots used responsibly have far more positive benefits for businesses and consumers than potential downsides. The future of the web will undoubtedly be bot-driven.

I hope this comprehensive overview shed light on the expansive world of bots online – their inner workings, evasion tactics and evolving trends. As someone who has built bots for over a decade, I‘m excited to see their capabilities advance – but also cautious of potential misuse without proper safeguards. Please reach out if you have any other questions! I‘m always happy to share my experiences around leveraging bots for efficient web automation.

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