Did your employer's IPO help your career?

If you witnessed the pains of growing a company to IPO level and been aware of the solutions applied in order to ease this pain and make the transition smoother, then you are very valuable for small companies that face the similar issues. For them, you are a "bar raiser".

Making a pile of money directly helps your career, because you can choose your opportunities instead of having to take a job that will pay the bills. You can do research, work on open-source, join an early-stage company -- whatever you'll learn the most doing.

Other than that, I don't think whether you stayed through IPO makes a big difference on your CV.

I work at Uber since 2017. There was a noticeable shift in priorities in the company related to efficiency and profitability (whereas before the IPO there was a lot of pie-in-the-sky stuff going on)

For me personally, there wasn't that noticeable of a difference in terms of career trajectory - my entire role is about creating efficiencies and I feel that my career would have progressed as it did regardless of IPO - but I saw other teams being negatively impacted. Many people were laid off in 2019 as a result of efficiency seeking initiatives from the leadership team, and others left as the company shed unprofitable verticals (e-mobility, and more recently self driving and aviation), and there were numerous structural changes internally as well.

In terms of career, IMHO the changes brought a lot of incidental opportunities to grow in terms of breadth of technical knowledge, but in a go-get-them-yourself sort of way, not so much mandated from the top.

Be prepared for it to get a lot bigger. That's one of the first noticeable changes when a company IPO's, they go on a hiring blitz either beforehand or after. I worked at a company pre-IPO that was 10 people, it ballooned to over 80 before I decided to move on. I love working in smaller teams where things have less red tape and when companies get that big, that's when the big sticky roll of red tape comes out. Another noticeable change is that freedom you might have to experiment and explore new features pretty much goes (unless your company is different). All of a sudden, the company has a responsibility to other people besides customers and more invested parties, things move slower and it can be frustrating.

In this day and age of marketing (especially for developers) it does look good on a resume to say you were an early employee at X company and were instrumental to its growth allowing it to IPO.

I did this once fully to IPO, and no it didn't really change anything for me. That said, when it happened I was younger and "just" a senior engineer, so I wasn't anyone who's decisions changed the company direction etc. Financially it was decent, but in other terms it didn't do a whole lot.

It did give me a brand name to reference at the time, but that fades quickly as you move forward. It helped for a short time in people recognizing the name and success so gave me maybe a slight leg up as we were known for having top talent. But outside of that, unless you can point to it and say you had some larger role then an IC role I don't think it will help you much. Director and above levels I feel it can make a change for your path as you'll be viewed as part of the "leadership" team that took the company public.