There are a couple reasons why we don't support importing the json file. First getting the json file on the device is slightly complicated. Second there is no native file picker so people would need to know the path to where the json file is stored. You will need to create a Sync account on desktop Firefox. https://support.mozilla.com/en-US/kb/how-do-i-set-up-firefox-sync Once you have that setup on desktop you will be able to enter the mobile device's Sync code in the Options window. https://support.mozilla.com/en-US/kb/add-a-device-to-firefox-sync Any questions about the specifics about a step please reply to this thread.