How do you say hey sup in Chinese?

There isn't a direct equivalent of "Hey sup" in Chinese, as it's a very informal and colloquial expression. However, depending on the context and the level of formality, you can use different phrases:

Informal:

* 你好！ (Nǐ hǎo!) - This is the most common and polite greeting, meaning "Hello!"

* 嗨！ (Hāi!) - A more casual "Hi!"

* 怎么样？ (Zěnme yàng?) - This literally means "How is it?" and is used to ask someone how they are doing.

* 你在干嘛？ (Nǐ zài gàn shénme?) - This means "What are you doing?" and is a casual way to start a conversation.

More playful:

* 嘿，兄弟！ (Hēi, xiōngdì!) - "Hey, bro!" (for male friends)

* 嘿，姐妹！ (Hēi, jiěmèi!) - "Hey, sis!" (for female friends)

Remember: The best way to use these phrases is to observe how native speakers use them in different situations and to adjust your tone and body language accordingly.