I'm a Mechanical Engineer. The company does Compressed Natural Gas fuel systems for heavy trucks and stationary power generation gas engines. Most cars run a 200 bar or 250 bar system, but to get additional fuel on board, we're using 350 bar cylinders on trucks. The gas compression and filling system needs to operate at up to 450 bar. It's serious pressure.
We're not involved in it, but the hydrogen systems run even higher pressure. In the US public filling stations for hydrogen cars usually have both 350 bar and 700 bar dispensing hoses.