- Is it always better to file a patent in United States first before extending it to other countries? What if we do the reverse: file patent in a small country then only extend it to the United States. What are the advantages?
- How would I file a US patent if I'm not a US citizen and instead a foreigner?
Many countries have rules associated with application filing that require you to file first in your home country. If the invention is made in the US, then you must obtain a "foreign filing license" from the USPTO before filing in another country.
The decision on where-to-file and the order-of-filing and depends upon (1) where will the exclusive right associated with a patent be most valuable; (2) how much it costs to file in particular locales; (3) which patent offices's work at the speed you want; and (4) are there agreements or practices that make it easier to get a patent in one locale after first obtaining a patent in another locale? Most US inventors file in the US first. This is explained in-part because of the foreign filing license requirement. However, it is also likely true that the US invention solves a US problem that will have a relatively large US market.
What is the advantage, it depends what strategy is best for you. It's probably easier and cheaper to start patenting in your home country or in your mother language. But you have to figure out where is the main market or where are the competitors. Or in other words which countries are most important for you. Maybe it's better for you to use PCT or European patent system, maybe Eurasian patent system. As I always recommend in these cases, consult it with some patent attorney. You can't find best answer in forums for that kind of questions. To give you some recommendations it is necessary to know more detailed background information. But it's not good to publish confidential information here.
Filing a first (priority founding) application in a particular country can be subject to other considerations than just business wise interest where you should have protection. As Dennis crouch already rightly has indicated, it may be that some countries require that an invention that has been done in their territory and/or by their citizens has to be filed in that country unless a foreign filing license is obtained. Next to the USA also France, the UK and India are examples of such countries.
A further criterion, also indicated by Dennis Crouch, is the language requirement. If you want to file in the USA, the application needs to be in English. If you would prefer writing in Spanish, the options are to file in Spain or any South or Middle American country (except for Brazil). Also the costs of filing can play a role, although you will experience that the filing fees that are required often are just a small part of the total cost of drafting and filing an application.
One important factor that has not yet been highlighted is whether or not the patent office where you will file your application will provide you with a novelty search and/or a preliminary opinion on the patentability of the claims of your application within the priority year. Although having such a search performed increases the costs at filing, it generally is a good way to judge the chances of success that your invention will appear patentable. And thus on basis of the outcome of such a search and/or patentability opinion you can decide whether it would be worthwhile to continue with the patenting process in other countries. Such a search and patentability opinion can be obtained by filing with the European Patent Office, or by filing in the UK, The Netherlands or PCT (in alle these cases it is possible to file the patent text in English).