Browser dev tools
Looking under the hood of a web page.
DevToolsA panel built into your browser that shows what a web page is made of and what it's doing behind the scenes.
Inspect elementPointing at any part of a page to see the code that draws it and the styles applied to it.
ConsoleThe DevTools tab where the page's code reports errors, warnings, and messages.
Network tabThe DevTools tab that lists every request a page makes, and whether each one worked.
Status codeThe three-digit number a server sends back to say whether a request worked, and if not, roughly why.
Stack traceThe list of lines under an error that shows exactly which code was running when it broke.
Device modeA DevTools view that makes your desktop browser pretend to be a phone or tablet.
Local storageSmall bits of data a website saves inside your browser, such as preferences or sign-in, that you can view and clear in DevTools.
Hard refreshReloading a page while telling the browser to ignore its saved copies, so you get the newest version.
LighthouseA built-in DevTools audit that scores a page on speed, accessibility, and best practices, then lists what to fix.