In the U.S.A., how much do you need to make from a project before it becomes a business? So lets say you do not have a U.S. citizenship but you spend a lot of time in the U.S. You buy products and create goods from them which you resell (say you build sheds out of wood or something of the kind). You have no employees and do all the work yourself. How much do you need to be making per year for it to be considered a business, which you would not be allowed to operate in the U.S. without citizenship or certain visas?
Less than zero dollars. An undertaking like this is usually categorized as either a hobby or a business. The official guidance is in IRS Publication 535, but a determinination takes into account lots of different factors, such as: how much time and effort goes into the undertaking; whether the taxpayer relies on the income for basic expenses; whether the taxpayer adapts his/her methods to increase profitability; whether the taxpayer has made profits this year or in years past; whether the taxpayer can reasonably expect to turn a profit in the near future. Even if you're losing money, the IRS may still say it's a business if all the signs suggest that that's what it is.
The Cayman Islands are well known as a tax haven. They have a corporate tax of 0%, and that includes income from abroad. So by moving your company officially to the Cayman Islands, you can avoid to pay a lot of taxes. Now of course most other countries will still send you a tax bill for any income you make with business activities within their borders. But there are accounting tricks to get around that. For example, many countries only tax profits, not revenue. So you can reduce your annual profits of your national subsidiaries to zero by having them pay money to your company on the caymans. For example, you can transfer your trademark to your subsidiary on the Cayman Islands and then have your subisdiaries in all other countries pay the Cayman company an annual license fee for using that brand name. And the license fee happens to be just so expensive that your national taxable profits become zero. And no, that's not just a Chinese thing. Corporations all around the world use that method to avoid taxes.
Under German law, yes sure. As long as you keep to all regulations. You have to declare your taxes. This is income, whether it comes from inside Germany or not and whether it is paid into a German bank account or foreign. You have to have a health insurance and likely need to pay into the social security and pension funds. As your employer most likely does not do this for you as a German employer would be required to, you will need to pay both the employee and the employer's part yourself. So yes, if you pay your taxes on it and have health and social security insurance, Germany does not care where the money comes from. Now whether the company in Mauritius is legally allowed to hire and pay you under their law? I have no idea. Please note that filling out all the right forms correctly is not for the faint of heart. And finding out that you did it wrong only years later is painful and costly. Also calculate your costs before you do anything. Paying both parts for your health insurance for example can easily be up to 400€ a month more then a German employee at a German company, so run your numbers. You may be better off being officially self-employed or even incorporated. Just because it's legal, does not mean it's a good idea. Hire a professional to advise you on the economic and bureaucratic side of this.
The tricky bit from a GDPR standpoint is that the US has a law that says a US-based company must hand over data to US government agencies even if the data is stored outside the US. This is US specific and a case where the US government gives itself jurisdiction outside the US but the EU can't directly do anything against it (outside of international negotiations). As you noticed this means if you store data at a US data processor there is no real difference whether the data is physically stored in the US or the EU. So to avoid transferring EU consumer data to the US several steps are needed. First the servers have to be physically located in the EU and second the company needs to be non-US based, EU based seems the obvious choice. AFAIK constructions of a US-based company creating a fully owned EU-based subsidary are currently used to achieve the second part. Whether this is sufficient may have to be decided in court.
You ask them explicitly, maybe adding that you need that info specifically to calculate tax. IP address is not reliable because your customers could be using VPN, Tor, or be on vacation overseas. (By the way, "IP" on a website about law would more likely be understood as "Intellectual Property", not "Internet Protocol address".)
You don’t need a company to run a business As an individual (sole-trader) you can operate a business, hire employees and contractors and do everything else a business does. The purpose of a company is to separate and protect your personal assets from your business assets. As a sole-trader you are personally responsible for all the liabilities of the business - if it goes bust, you go bust. If the business is operated by a company, then, providing you and the company follow the law, your personal assets are not at risk if the company becomes insolvent.
By &quot;unlicensed&quot; you mean that it doesn't state a license for use (MIT, GPL, etc.)? Those licenses are just a codified bundle of terms of use that cover many many edge cases. You have in place a much simpler agreement that covers the primary situation: you using/modifying the code for your own use. It's just like borrowing a car. You will ask a friend &quot;hey, could I borrow your car for a bit?&quot; &quot;sure!&quot;. You know there's a possibility that you'll get in an accident or something weird will happen, but you think the chances of that are minimal and you would be able to work it out. If you ask a car rental company, they'll give you a full contract covering every situation that may happen. Similarly, a large company would be hesitant to borrow a car for corporate use without a legal framework surrounding it. So you will likely be in the clear if you are just using it for a small project with minimal legal/financial implications. If you plan on turning your project into a multi-billion dollar empire, you should revisit your agreement.
Germany may be different, however in the United States this would be considered work-for-hire and the employer would be the rightful owner of the source code. Regardless of jurisdiction, and from a more practical point of view, you are better off not having a copy of the source code. Using it as reference or example in the future could easily turn into (unintentional) copyright infringement. If, in the future, you write code you would like to be able to freely keep and reuse in any project, make sure the owner/employer licenses it using something like the BSD, MIT, or ISC license.