It can be. Depending on configuration you can run with or without master. (https://docs.saltstack.com/en/latest/topics/tutorials/quicks...)

No, an agent runs on the host (a "minion") and calls back to a ("master") for instruction. Masters pub messages to minions with job IDs, and minions execute and respond accordingly. The minion is very lightweight. Masters less so, but they vertically scale pretty well.

Saltstack can be used without both salt-minion and salt-master daemon, it is called masterless mode.