What is the Rotational Software Engineer Program?
How is it different from a regular SWE role?
Is it like being a contractor hired through a staffing company?
Are there levels to it (E4/E5, etc) or is it just one level?
Is there a good chance to become a fulltime employee afterwards and is this a good way to join Meta?
Is it a decent career move to join such a program if you are already a senior in another company or will you be considered a noob if you join a role like this?
I have actually worked alongside rotational SWEs at Meta, so I can go through how the program works. Unfortunately, I didn't know any of them too closely so I can't give any details on specifics like comp. Anyways, here's a bunch of details:
The problem with being a rotational engineer is that you can't build up good relationships as you rotate after 6 months. Being a "Meets All Expectations" E4 isn't trivial in this economy either: Meta is cranking up stack rank and PIP percentages to fire more engineers. I have worked with a lot of senior engineers who probably couldn't survive as an E4 in this market.
What I will say though is that despite all the shortcomings, Meta is still Meta. You'll learn a lot as a rotational engineer (especially in code review), and there's a clear path towards a proper FTE offer. With Taro on your side, you would have a better chance than most. If you can't get into Meta as an E4/E5, I think it's worth giving the program a shot.
Meta E4 offers can get pretty high too - I have seen $325k TC in some cases, though I imagine a rotational engineer offer would be bottom of band, not top. Still, even something like $250k would be higher pay than most senior engineers. Meta is also extremely generous with high performers. A "Greatly Exceeds Expectations" rating could increase an E4's comp by $35k - $50k. So even if you get in as bottom of band, you can work your way up.
Interesting side note: There is a rotational PM program at Meta as well but they get 3 halves.
Alex gave a great answer, I just wanted to provide an opinion on your last question:
Is it a decent career move to join such a program if you are already a senior in another company or will you be considered a noob if you join a role like this?
Worry much less about the title, and worry much more about (1) what opportunities the job creates for you and (2) your compensation.
For example, some banks will give out the Vice President title like candy, with a non-trivial % of the engineering team called VP 😅 However, there are some mid-level engineers in FAANG who get paid more.
So in that case, I'd forget the title (it's fake anyway) and take the FAANG job. Compensation is a proxy for importance to the company, so take the job where you get paid more and the company will likely invest in you more.
So, short answer, YES! Rotational eng is a great program if you use it as your entry point into Facebook.
Some great thoughts here: How should I think about levels when it comes to evaluating jobs and in my career overall?