SelectorsHub: Best XPath AddOn for Firefox.
After deprecation of FirePath and chropath, it was really difficult to write and generate xpath on Firefox but then Chropath creator invented new tool SelectorsHub which is very advanced and has amazing features.
SelectorsHub is the Next Gen XPath tool to generate, write and verify the XPath and cssSelectors. It supports shadow dom, iframe, svg, dynamic elements, multi selectors generation and error handling.

Very simple steps to use SelectorsHub-
1. Open DevTools.
2. Click Click on the last sidebar tab on the right hand side, i.e. SelectorsHub
3. Here it will show all possible selectors for inspected element.
Inspect the element for which you want to generate the selector and it will generate all possible selectors for that element.
4. To build your own XPath or cssSelector, start typing in the selector input box.
5. SelectorsHub will automatically suggest all attributes and everything to complete Selectors quickly. Now you need not to copy and paste attribute values anymore. With this you can save a huge amount of time.
6. After typing, just press enter.
7. It will highlight all matching nodes and list them down in the SelectorsHub tab.
8. It will also scroll the web element to the viewable area.
9. To copy the selector’s value, click on the copy icon.
10. To edit selector’s value, click on that selector value