What Does Your User Agent Say About You?


A user agent is a computer program representing a person, for example, a browser in a Web context.

Besides a browser, a user agent could be a bot scraping webpages, a download manager, or another app accessing the Web. Along with each request they make to the server, browsers include a self-identifying User-Agent HTTP header called a user agent (UA) string. This string often identifies the browser, its version number, and its host operating system.

Spam bots, download managers, and some browsers often send a fake UA string to announce themselves as a different client. This is known as user agent spoofing.

The user agent string can be accessed with JavaScript on the client side using the navigator.userAgent property.

A typical user agent string looks like this: "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0".


User Agent String

Browser Data

Firefox Googlebot User Agent

Maria Garcia
• Tuesday, 05 July, 2022
• 48 min read

User agent is an HTTP request header string identifying browser, application, operating system which connects to the server. Not only browsers have user agent but also bots, search engines crawlers such as Google bot, Google AdSense etc.



“Crawler” is a generic term for any program (such as a robot or spider) that is used to automatically discover and scan websites by following links from one webpage to another. This table lists information about the common Google crawlers you may see in your referrer logs, and how they should be specified in robots.txt, the robots meta tags, and the X-Robots-Tag HTTP directives.

Some pages use multiple robots meta tags to specify directives for different crawlers, like this: Google uses a Chrome-based browser to crawl and render webpages so it can add them to its index.

Web servers can use user agent information to change how they serve the page. The user agent string is also what helps Sees analyze their log files and understand which pages Google is visiting.

Since Google bot is now always using the latest version of Chrome, the user agent string should reflect that. This means that not only will Google bot run the current version of Chrome, give or take just a few weeks, but its user agent string will then update to include the current version numbers for identifying itself.

An evergreen Google bot means leaps and bounds for your render budget. Where JavaScript’s impact on SEO may have had negative consequences for your website previously, now Google bot can navigate more modern JS language as it continues to update alongside Chrome.

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This means that the updated user agent has opened the door to 1,000+ JavaScript features. Additionally, you no longer need to use as many polyfills in JavaScript for functionality in older browsers for Google bot.

Previously, when Google bot used an outdated version of Google Chrome, it was important to use polyfills. Our rendering will always match or exceed Google bot ’s, giving you the most accurate picture of your SEO data.

Google recommends that you use feature detection and progressive enhancement instead of user agent sniffing, a tactic sometimes used by smaller, non-enterprise websites. Feature detection identifies Google bot by matching its capabilities to known features that Google bot supports, while progressive enhancement ensures that websites serve their preferred, full-feature experience to browsers that can handle it while serving a more simple webpage to those that can’t.

Using feature detection and progressive enhancement are the more scalable options for enterprise websites long-term and make even more sense now that Google bot ’s user agent string will continue to update. Therefore, Google’s change to the user agent string will have no impact on Notify’s reporting.

The only factors that Sees should consider in regard to the new string, and the previously announced evergreen Google bot, is a) reevaluating their usage of polyfills, b) implementing feature detection and progressive enhancement (if they don’t already), and c) keeping an eye on the two points above as suggested by Google. By changing user agent, sometimes, one can get access to restricted part of a website with extra contents that normally open only to bots, or search engine crawlers.

firefox browsing mozilla registration without website using googlebot bot agent user

This kind of area typical example is “Member Only” forums or sites that don’t want to lose out on search engine traffic. Modification of user agent string also enable surfers to trick websites into believing that they are actually using a particular web browser or using specific system in order to avoid and disable advertising display or junk ads that targeted to specific segment of viewers of the websites only. Once installed and restarted Firefox, simply go to Tools Sergeant Switcher, and you will see a list of user agents which you can choose.

To change back to the default user agent, simply right-click on the line and select Reset. OK is a technology writer for Tech Journey with background of system and network administrator.

He has be documenting his experiences in digital and technology world for over 15 years. Connect with OK through Tech Journey on Facebook, Twitter or Google+. There are a bunch of reasons you may want to trick a website into thinking you’re using a browser other than Firefox.

These unwanted bots scrape and steal your content, post spam on forums, and feed intel back to competitors, all while claiming to be an innocent Google bot. Some of these fake bots have been reported to even act like Google bot, crawling your site similarly to further avoid detection.

For each record, it does a reverse DNS lookup of the client’s source IP address to see if it resolves to the search engine’s domain, such as google bot .com. Of course, these steps could be performed manually, but allowing HAProxy Enterprise to do it automatically for each unverified bot will save you huge amounts of time and labor, especially since Google sometimes changes the IP addresses it uses.


It also fits in with the other bot management mechanisms offered with HAProxy Enterprise to give you multiple layers of defense against various types of malicious behavior. Mealtime Cluster-wide Tracking, which deploys behavior analysis across your cluster, and Access Control Lists (Acts), which are pattern-matching rules, that together allow you to track requests from the same client and discover patterns of anomalous behavior, such as web scraping or login brute forcing attempts.

Together, these countermeasures keep your website and applications safe from a range of bot threats, but without compromising the quality of the experience regular users get. Verify Crawler comes included with HAProxy Enterprise and is yet another way to protect your website and applications from bad bots.

Impersonating Google bot or other search engine crawlers has been an easy way for attackers to evade detection until now, with few website operators having the time or resources to combat it. It powers modern application delivery at any scale and in any environment, providing the utmost performance, observability, and security.

Organizations harness its cutting edge features and enterprise suite of add-ons, backed by authoritative expert support and professional services. Note: While working on this blog post, coincidentally, a thread was started on the mailing list around this subject.

To do so, simply visit our project on the Debate hosted instance, create an account and either select an existing language or add a new one to get going. This way it becomes much easier for me to keep track of reported issues and get back to you if additional information is needed to help you.

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And yes, the Browser data is here to stay and if you cannot cope with the extra size this causes please kindly download a different extension and don't down-vote. If you ever wanted to make your web traffic seem like it was coming from a different browser–say, to trick a site that claims it’s incompatible with yours–you can.

If you don’t see the console at the bottom, click the menu button in the top right corner of the Developer Tools pane–that’s the button just to the left of the “x”–and select “Show Console”. On the Network conditions tab, uncheck “Select automatically” next to User agent.

It only works while you have the Developer Tools pane open, and it only applies to the current tab. To create the preference, right-click on the about:config page, point to New, and select String.

You can find extensive lists of user agents on various websites, such as this one. This setting applies to every open tab and persists until you change it, even if you close and reopen Firefox.

To revert Firefox to the default user agent, right-click the “general.user agent.override” preference and select Reset. Microsoft Edge and Internet Explorer have user agent switchers in their developer tools, and they’re nearly identical.

string agent googlebot

To open them, click the settings menu and select “F12 Developer Tools” or just press F12 on your keyboard. The developer tools will open in a separate pane at the bottom of the window.

It only applies to the current tab, and only while the F12 Developer Tools pane is open. Chris has written for The New York Times, been interviewed as a technology expert on TV stations like Miami's NBC 6, and had his work covered by news outlets like the BBC.

Since 2011, Chris has written over 2,000 articles that have been read more than 500 million times---and that's just here at How-To Geek.

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