Hi.. could anyone confirm if applying for a visa online is legit? specifically for a vietnam visa?

Yes. Apply online for Vietnam visa is legit. When you do that, you will be issued a visa approval via email and you will have to use this approval to get visa stamp at the airport on arrival. For this reason, Vietnam visa online is also known as Vietnam visa on arrival.

You can find more details about this visa at vietnamvisa-easy.com