Despite any possible doubt, everything's cool.

Means nothing is bad.

Used in an optimistic sense to show the lightheartedness of something.

typically means by saying it's cool or it's okay when someone apologizes.

Just like saying it is ok. When someone says sorry it would be relevant to use this phrase

its all good - the best way to live your life.

Everyone/ Everything is cool.

Whoever you are/ Wherever you're from, you're alright with me.

Platitude that covers so many emotions and situations that it says little; its only real meaning is that the speaker is trying to rise above whatever problem exists, without expressing their underlying negative emotions. (They might be angry, sad, upset, frustrated, hurt, disappointed, etc.) Often used in a passive-aggressive way. Rarely, used compassionately for someone else, trying to make them feel better. A favorite of inarticulate teens; fills in the gaps between: like, dude, dudette, whatever, so, I dunno, hey, etc.