Developer Tools
Developer tools (or "development tools" or short "DevTools") are programs that allow a developer to create, test and debug software.
Current browsers provide integrated developer tools, which allow to inspect a website. They let users inspect and debug the page's HTML, CSS, and JavaScript, allow to inspect the network traffic it causes, make it possible to measure it's performance, and much more.
See also
- Web development tools on Wikipedia
- Firefox Developer Tools on MDN
- Firebug (former developer tool for Firefox)
- Chrome DevTools on chrome.com
- Safari Developer Tools on apple.com
- Edge Dev Tools on microsoft.com