You want to start as an entrepreneur but you do not want to quit your job? That is quite possible. You do not even need to tell it your employer (under certain conditions). In fact you can combine paid employment and self-employment. This is particularly handy for testing a prior idea before really starting. Be registered with the tax administration and VAT also allows you to deduce your first creation costs immediately (under certain conditions). Also potential trade losses can be offset against your salary. This allows some tax savings. Finally, if you achieve a turnover of less than one third of the minimum wage, you can ask to be exempted from the minimum social security contributions. However you must not compete directly with your employer. You should also check that you do not have an exclusivity clause in your employment contract. For more information contact me!