You are in the US as well. We have FICA (social security, medicaid, Medicare) of which half is paid by the employer and half employee. If you hear "self employment tax", that's typically referring to the fact that you're paying both sides (15.3% over 7.65%).
There are a few more nuances, but that's the gist of it.
Thanks. The state (or most states) tacks some on as well, right? If I was not self-employed my employer/client and I would be paying into Employment Insurance and Canadian Pension plan as well, but I'm able to skip that as I own more than 20% (don't recall the exact percent they require for exemption) of the corp I work for. There is also 13% sales tax but I stack that on top of my hourly. I can claw back some of the sales tax by claiming the tax I paid on business expenses.
Oh yes, I was only covering federal taxes. To my knowledge, the general structure in most states doesn't matter. I don't know of any states where income taxes are partially paid by the employer and partially by the employee (like FICA).
There are a few more nuances, but that's the gist of it.