CTO/VP Engineering have the same separation of tasks as CEO/COO.
The CTO is the chief engineer he or she sets technical direction for the company. VP of Engineering is the top manager for that division and executes the CEO’s vision using technical choices made by the CTO.
In many companies these are the same person, but not always. In my last startup they were separate people. The best chief engineer (CTO) isn’t always a good people person (VP).
Software companies that differentiate by some metric other than core technology might not need a CTO, which would explain your confusion if that’s your background.
"The CTO is the chief engineer" is both false and somewhat circular. It's false because plenty of "CTOs" --- maybe most of them! --- work outside the engineering organization, and are more closely aligned with product management than software development (CTO is very often a customer-facing "role"). It's circular because it leaves open the question of what a "chief engineer" is.
I worry that a lot of HN "CTO discourse" is really wishcasting, about what an "if I was monarch of all the developers" role would be (and then about what it's like to aspire to such a role). No healthy engineering team has such a person!
Wow. I would run, not walk, away from any tech company that had this role.
Since you asked: I'm one of the principals at Fly.io. Before that, I was one of the founders of Latacora, which embeds directly inside of startups for years at a time running their security teams full time. Before that, I founded Matasano Security. Before that, I was a Product Manager at Arbor Networks, after being the lead developer on their DOS product for a couple years. I'll stop there (I'm older than the median HN commenter).
Later
For what it's worth, for companies literally chartered to do scientific exploration --- drug discovery chemistry, for example --- I completely buy that there is a real "Chief Scientist" role, though I can't claim to understand that role well enough to defend it. But that doesn't describe any software company anywhere. Regardless, "CTO" is something different.
The CTO is the chief engineer he or she sets technical direction for the company. VP of Engineering is the top manager for that division and executes the CEO’s vision using technical choices made by the CTO.
In many companies these are the same person, but not always. In my last startup they were separate people. The best chief engineer (CTO) isn’t always a good people person (VP).
Software companies that differentiate by some metric other than core technology might not need a CTO, which would explain your confusion if that’s your background.