Show Safari's Develop menu to change the user agent

A site tells you to "use Chrome," or your own page serves different markup depending on the browser, and you need Safari to identify as something else. Safari can spoof its user agent — the string it sends to say what browser it is — but the control lives in the Develop menu, which is hidden by default. Enable that menu and Develop → User Agent lets you pose as Chrome, Firefox, Edge, or mobile Safari in a couple of clicks.

Show the Develop menu

The User Agent switcher is a Develop-menu item, so make that menu visible first:

1. Open Safari → Settings (Cmd+,) and click Advanced.
2. Tick Show features for web developers on macOS 14 Sonoma and 15 Sequoia, or Show Develop menu in menu bar on macOS 13 Ventura and earlier.
3. Close settings — the Develop menu is now in the menu bar.

Switch the user agent

Open the page you want to test, then choose Develop → User Agent. The submenu offers:

• Default (Safari) — Safari's real identity, ticked until you change it.
• Named browsers — recent Chrome, Firefox, Microsoft Edge, and Internet Explorer strings, plus Safari — iOS and Safari — iPadOS for mobile.
• Other… — a field where you can paste any custom user-agent string you need.

Pick one and the current tab reloads immediately, now reporting that browser. This is per-tab and temporary: the setting resets to Default when you close the tab or quit Safari, so you never have to remember to switch it back. To return sooner, choose Develop → User Agent → Default.

What it does and doesn't change

Changing the user agent only changes the identity string the browser reports. It's genuinely useful when a site's server or JavaScript makes decisions based on that string — a login page that blocks "unsupported" browsers, or your own code branching on the UA. Combine it with Responsive Design Mode, which sets the iOS user agent automatically when you pick an iPhone, and you can reproduce a lot of mobile behavior from your desk.

What it doesn't do is turn Safari into Chrome. The page still renders in WebKit, so a Chrome-only rendering quirk won't appear just because you claim to be Chrome. Treat the switch as a testing tool for UA-conditional logic, not a compatibility fix.

Enable the menu from the Terminal

# Show the Develop menu (home of the User Agent switcher)
defaults write com.apple.Safari IncludeDevelopMenu -bool true

# Undo
defaults write com.apple.Safari IncludeDevelopMenu -bool false

Quit Safari and reopen it afterward. On recent macOS, Terminal needs Full Disk Access (System Settings → Privacy & Security) for this write to stick; if it doesn't, the Advanced-tab checkbox always works.

When a site really needs another browser

If a site genuinely won't work in WebKit, spoofing the UA won't save it — you may just want a different default. See how to change the default browser on Mac to route those links elsewhere.