Is "Hope you're doing well" correct or should I use "Hoping you're doing well"?

[Zoli]

Hi, I want to send an email to a friend I've talked to on Messenger but haven't emailed before, even though it's been a while since we last spoke. In the email, I asked him if he's still passionate about computer programming and shared with him some updates. I want to send this e-mail with the subject "Hope you're doing well". Is that correct for a subject line or should I use "Hoping you're doing well"?

 

[jutfrank]

Hope you're doing well.

It's more of a greeting line than a subject line.

 

[emsr2d2]

Like jutfrank, I wouldn't make that the subject line. Use something like "Hi! It's been a while" or something similar. Start the main body of the email with:

Hi, [name]

Hope you're doing well.