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.
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 agents are also critical in controlling search engine robots using the robots.txt file on your server. In order to leverage this information, you need to understand the component parts of an user agent string and consider also the potential risks of using this method to deliver content.
When the internet was a text-based system, right back at the beginning of its use, users had to type commands to navigate and send messages. We simply point and click, and the browser is acting as our agent,” turning our actions into commands.
This is a really set of data for web developers since it allows them to customize the experience depending on the user agent that's loaded the page. Browsers are a straightforward example of an user agent, but other tools can act as agents.
Plus a whole range of feed readers, validators, cloud platforms, media players, email libraries, and scripts. Once the user agent has identified itself to the web server, a process called content negotiation can begin.
The user agent application is Mozilla version 5.0, or a piece of software compatible with it. Note that a huge part of the user agent string is concerned with compatibility.
That's because Internet Explorer originally had to declare itself to be Mozilla compatible in order to receive content with frames. In practice, the majority of browsers now declare themselves to be Mozilla compatible to ensure that they can access all the content on the web.
More, we can feed that data back into a cycle of continuous improvement, analytics and other processes, like conversion optimization. As we mentioned in the introduction, search engine crawlers are a very specific type of user agent.
An user agent is a particular string of characters in each browser that allows acts as an identification agent. The user agent string contains the user application or software, the operating system (and their versions), the web client, the web client's version, and the engine responsible for the content display (such as Apple WebKit).
It is a rendering engine that processes HTML and CSS to interpret and present web pages. WebKit is also responsible for allowing you to navigate through links on a web page.
There's no “standard” way of writing an user agent string, so different web browsers use different formats (some are wildly different), and many web browsers cram loads of information into their user agents. Some mobile web browsers will let you change what the browser identifies itself as (i.e. “Mobile Mode” or “Desktop Mode”) in order to access certain websites that only allow desktop computers.
English French German Spanish Portuguese Slovak Armed with this information, you can develop richer and more dynamic websites that deliver different experiences based on the user agent that is visiting.
It is a large pool so there is a lot of room for randomization, which can allow you to stay more anonymous. Look around to find user agents for whatever browser, operating system, device, software type or layout engine you need.
However, switching your browser’s user agent no longer requires that you install third-party software, such as extensions. Over the past few years, mainstream browsers have all started including such functionality as a part of their developer console or within standard menus.
Although uncommon, there is a chance for browser extensions to become hijacked for malicious purposes, which could be a risk to your security. If you look or scroll down towards the bottom of this panel, you should see a User agent label, which includes a respective set of options.
Here, you can select from a set of defined user agents or even enter your own custom user agent string. If it’s your first time doing so, you should see a disclaimer stating that you’re entering risky territory that’s for advanced users only.
Since 2008, he's worked remotely with some of the most notable publications in these industries, specializing in Windows, PC hardware and software, automation, and the like. Practically every time you access a high-traffic website, its server will be taking into account what your current user agent is, which helps identify your operating system and browser, in an attempt to better deliver content to you.
Even popular browsers such as Chrome, Firefox, and Safari can often display web content in inconsistent ways when compared with each other. But there are hundreds of user agents out there, ranging from browsers you’ve probably never heard of to email and RSS readers.
In this article, we’ll discuss the technical side of user agents and how you can take advantage of software and browser plugins to manipulate how content is shown on the web. This information is passed to web servers via HTTP headers, and it can be used to change the way that content is displayed.
While an user agent won’t identify you anywhere near as narrowly as an IP address, you’re still giving up the way you browse. Nowadays, most popular browsers include a developer console that will allow you to change all sorts of things, such as your viewing resolution and user agent.
This Chrome extension has nearly two million total users and was developed by Google, so its compatibility with the browser should be as good as you’ll ever find. Once installed, this extension adds a button to the right of the address bar that allows you to select through a total of eight browsers and mobile operating systems.