Hautjob + Minijob + Gewerbe?

The trade must of course be registered and you must make corresponding tax returns. Depending on the amount of profit, taxes are also to be paid. But you don’t have to worry about it. High taxes mean you earned a lot of money. That’s good. No one pays for 1000€ additional income at the end to control over 1000€. It would be 47.475% maximum (with Reichensteuer and Solz). But you would have to earn six-digit in total

the minijob is probably taxed by the employer. The income will then remain out of line. But the profit from the trade will be counted with your other incomes that you as a worker and then taxed together, with already paid wage tax being calculated as a prepayment. Depending on the amount of the profit, a repayment will of course come. Depending on the amount of your total income, I would plan about 1/3 of the profit from the industry

the revenues are also subject to VAT. Whether the small business operator scheme is sensual (conversions up to 22,000) or not, for example, because you spend predominantly performance for other entrepreneurs entitled to pre-tax deduction, you should clarify with a tax advisor

for a 40h full-time job, this is probably not relevant, but if the business was more time- or economic than your job as a worker, it would be no longer in the sense of social security. You would then no longer be legally insured in statutory health insurance, but voluntarily insured in law, then the profit is payable on a fee or would have to be insured privately