My company is not in US,UK or Germany.
I wonder that I can develop a gadget with Amazon in other countries?
Here is a snippet from the documentation located here:
There are no language and locale limitations for skills where the use of Alexa Gadgets is optional. However, when you choose which languages and locales to support, note that Alexa Gadgets are available in US, UK, Ireland, Germany, and Austria only. You should therefore distribute your skill to at least one of the countries in that list. If a skill requires the use of an Alexa Gadget, the skill can only be used in countries where Alexa Gadgets are available.