bitwarden takes extreme measures to ensure that its websites, application, and cloud servers are secure. Part of this security comes from the fact that we rely on managed services and do not manage our cloud server infrastructure at all.
However, if for some reason bitwarden were to get hacked and your data was exposed, your information is still protected. This is because bitwarden uses strong encryption and one-way salted hashing. As long as you use a strong master password, your data is safe no matter who gets ahold of it.