Every time a browser opens a website, it sends information that helps the server decide what content to return. One of the most familiar signals is the user-agent string, a line of text that may identify the browser family, operating system, device category and software version.
The first question is simple: what is a user agent? In practical terms, it is an HTTP request header used by websites to distinguish Chrome from Firefox, Windows from Android and desktop traffic from mobile traffic. Developers rely on it for compatibility testing, while marketers and privacy-conscious users may change it to inspect regional or device-specific experiences.
Changing the string is easy. Making the entire browser environment consistent with it is harder.
How to Check Your Current User Agent
The quickest method works in Chrome, Firefox, Edge, Safari and Brave. Open the browser’s developer console and enter:
navigator.userAgent
Press Enter, and the browser will display the user-agent value available to JavaScript on that page.
A desktop Chrome string might look similar to this:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36
The strange mixture of names is the result of decades of browser compatibility decisions. Chrome mentions Mozilla, AppleWebKit and Safari because many websites historically looked for those identifiers before serving compatible content.
Checking navigator.userAgent is useful, but it is not always the complete picture. Chromium browsers also send User-Agent Client Hints through headers such as Sec-CH-UA, Sec-CH-UA-Mobile and Sec-CH-UA-Platform. A site may compare these values with the traditional user-agent string.
Developers can see the actual request headers by opening DevTools, selecting Network, refreshing the page and clicking the main document request. The user-agent information appears under Request Headers.
How to Change the User Agent in Chrome
Chrome provides a temporary override through DevTools. It is intended primarily for testing how a website responds to different browsers and devices.
Open the page you want to test and press F12 or Ctrl + Shift + I on Windows and Linux. On macOS, press Command + Option + I. Open the DevTools menu, select More tools, and choose Network conditions.
Under User agent, clear the Use browser default or Select automatically checkbox. Chrome will then let you select a predefined option or enter a custom string. Refresh the webpage after choosing the new value.
Recent Chrome versions also allow developers to edit User-Agent Client Hints in the Network conditions panel. This matters because changing only the traditional string can produce contradictory information for example, an iPhone user agent accompanied by a Client Hint identifying Windows.
The DevTools override is temporary and normally applies only while the tools remain open. It is excellent for debugging responsive layouts or browser-specific messages, but inconvenient for daily work.
How to Change the User Agent in Firefox
Temporary Testing in Responsive Design Mode
Firefox includes Responsive Design Mode, which can simulate different mobile devices. Open it with Ctrl + Shift + M on Windows or Linux and Command + Option + M on macOS.
Users can select a predefined device or create a custom device with its own viewport size, device-pixel ratio, touch setting and user-agent string. This is the safest Firefox method for developers because it keeps the change tied to a testing session.
Changing the Firefox User Agent Through about:config
Firefox also allows an advanced browser-wide override. Enter about:config in the address bar, accept the warning and search for:
general.useragent.override
If the preference does not exist, create it as a String. Paste the required user-agent value and restart or refresh the relevant tabs.
This approach can affect every site opened in Firefox. To restore normal behavior, return to about:config and delete or reset the preference.
A browser-wide override can cause websites to display compatibility warnings, deliver unsuitable downloads or send a mobile layout to a desktop computer. It should therefore be used carefully and documented if the browser is shared with other employees.
How to Change the User Agent in Microsoft Edge
Because Edge uses Chromium, its DevTools process is almost identical to Chrome.
Open DevTools, press Ctrl + Shift + P on Windows or Command + Shift + P on macOS, type Network conditions, and select Show Network conditions. Clear Use browser default, choose a preset or enter a custom string, and reload the page.
Edge can also emulate User-Agent Client Hints. Developers testing a mobile configuration should update the browser brand, full version, platform, architecture and device model where necessary. Changing the visible user-agent string while leaving every Client Hint at its original value creates an incomplete test.
As with Chrome, the DevTools override is temporary. A trusted extension may be more convenient for repeated testing across many sites, while managed organizations can distribute browser settings through administrative policies.
How to Change the User Agent in Safari
Safari offers a straightforward built-in method on macOS. First, open Safari > Settings > Advanced and enable Show features for web developers. In some Safari versions, the option may be labeled Show Develop menu in menu bar.
A Develop menu will appear in the macOS menu bar. Open it, choose User Agent, and select one of the available browser or device presets. Safari may offer options representing Safari on iPhone or iPad, as well as other desktop browsers. A custom value can be entered when a preset is not suitable.
The override is mainly a testing tool. It does not transform a Mac into an iPhone, add a touchscreen or reproduce iOS hardware. For accurate mobile testing, developers should use device emulation or test the website on an actual iOS device.
Safari on iPhone and iPad does not provide an equivalent interface for arbitrary user-agent strings. The Request Desktop Website option can ask a site for its desktop experience, but it is not a full custom user-agent editor.
How to Change the User Agent in Brave
Brave is Chromium-based, so it uses the same Network conditions workflow as Chrome.
Open DevTools, select More tools > Network conditions, disable automatic user-agent selection and choose a preset or enter a custom value. Refresh the page while DevTools remains open.
Brave includes additional fingerprinting protections, but those protections should not be confused with a complete custom browser identity. A changed user agent can still conflict with the platform, screen resolution, graphics data, time zone or Client Hints detected by a website.
For permanent switching, Brave users can install a Chromium-compatible extension. The extension should come from a reputable developer and request no more permissions than necessary.
Should You Use a User-Agent Switcher Extension?
Extensions are convenient when the same user agent must be applied repeatedly or only on selected domains. A good switcher can maintain several presets, create site-specific rules and return to the browser default without opening DevTools.
The trade-off is access. Depending on its design, an extension may be able to read browsing activity or modify requests. Check its permissions, privacy policy, update history and developer reputation before installation.
Extensions are suitable for website testing and occasional compatibility work. They are less dependable when separate accounts require stable, long-term environments because they usually change only a narrow set of browser signals.
When Browser Profiles Are a Better Option
A browser profile stores cookies, sessions, proxy settings and other configuration separately. This is more practical than repeatedly changing one global user agent when a team works with several test environments, client accounts or regional websites.
Antidetect browsers such as Gologin let users create individual browser profiles and configure the user agent alongside the operating system, proxy, screen parameters and related fingerprint values. Profiles can then be shared with team members without combining every account inside one browser environment.
Consistency is the main advantage. If a profile claims to be Chrome on Android but reports macOS through other APIs, the mismatch can be more distinctive than the original configuration.
Changing the User Agent Does Not Change the Device
A user-agent override changes what the browser reports through a specific string. It does not automatically change the IP address, operating system, installed fonts, WebGL renderer, Canvas output, screen resolution, language or time zone.
It also does not bypass authentication, platform policies or access controls. Its legitimate uses include cross-browser development, debugging, mobile layout checks, compatibility testing and controlled privacy research.
After changing the user agent, verify both navigator.userAgent and the headers in the Network panel. Then check the rest of the environment. The most reliable setup is not the one with the most unusual user-agent string; it is the one in which all reported browser and device signals make sense together.
