Vaultpass is a site-specific password generator based on the domain you are visiting and the passphrase. It is based on the open source Hashpass and Vault. Hashpass provides an easy-to-use interface and vault provides the algorithm based on PBKDF2. While there is no shortage of password generator and manager, a lot of them depends on their web services or sites, which you need to trust. Vaultpass uses chrome extension to avoid hosting any of its code online and it is hosted on github.
You need to remember your single passphrase and domains in order to generate site-specific passwords. Some websites have different domain names depending on how you reach it. Therefore, you might need to simplify the domain name manually. Since the algorithm of Vaultpass is open sourced, you can also add some prefix or suffix on the domain names to make dictionary attack more difficult. No password is uncrackable. It just takes time and effort. By using Vaultpass for site-specific password, you can avoid the hacking of one site affecting your security on other sites.
These passwords might also be used on mobile apps and it is much difficult to input the password on mobile phone. An app is currently under developement so that you can easily input the sample password on desktop and mobile phone.