[camdat]

Which EU country has a non-progressive tax rate?

[danielEM]

Poland offers flat tax rates: 12% for IT entrepreneur or 19% for employees.

[isbvhodnvemrwvn]

That's not quite right, if you have a single person company (with unlimited personal liability) you can choose between revenue and income tax. Both are flat rates, revenue is 12% for certain groups of companies, including software engineering with revenues below several million euro, income tax is 19% universally.

[devilirium]

Hungary