There are two common phrases that you will hear for “good job”. From my experience, the first one is more casual than the second and I hear it used towards younger people a lot.
The second one is what you can use towards coworkers and workers you may see at shops.
The first one literally means “You did well”:
Formal 잘 했습니다. (jal hae-sseum-ni-da)
Standard 잘 했어요. (jal hae-sseo-yo)
Casual 잘 했어. (jal hae-sseo)
For the second one, it’s more formal than the first, & you would use it towards someone who just finished doing some hard work:
Formal 수고하셨습니다. (su-go ha-shyeo-sseum-ni-da)
Standard 수고했어요. (su-go hae-sseo-yo)
Casual 수고했어. (su-go hae-sseo)
– “Thank you for your hard work”
– “Good work.”
– “Congrats on finishing your work.”