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.
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!
What industry are you in? In deep-tech / hardware the role of chief engineer is well understood. In biotech it is sometimes called chief scientist.
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.
Recently watched a relatively young person parley a position at a small company with a VP title that resulted in a slot at a regionally well known organization as a director and then president of a much larger startup.
Over about 4 years he went from front line sales to running a sizeable company with the key step being the VP title at the small company that rocketed him up.
I also recall a former co-worker that was denied promotion and generally failing to progress in his career. He took a slot at a tiny company explicitly for the title. I think it was director. He managed to parlay that into very positive career moves.
Personally, I don't care as much about titles these days. I just don't want to work for places making terrible tech decisions and forcing me to work within that. I'm happiest making the decisions and really don't want to stop, whatever it's called.
1. The corporate officer title a founder that isn't the CEO gets because they're on the board, purely as recognition of their seniority ("why is this person on the board?" "because they're the CTO.")
2. The consolation prize a founder or early employee gets when the mature engineering organization takes away their commit privileges.
3. The fluffy title a founder or senior employee gets when they transition to a customer-facing role so that prospects are (ostensibly) impressed.
These are all situational and don't really describe a "role". Excepting case (1), I would be a little alarmed if a company I worked at asked me to assume a "CTO" role. Either way: having been a "CTO" says basically nothing at all about whether you're lateral to software developers.
Your question makes more sense if you consider the move from VP/Engineering to developer. Either way, you're completely fine from a signaling perspective, but you're especially OK if your title was "CTO" and not "VP/E". The last thing in the world you should want is a career trajectory defined by "CTO-hood". Yikes!