But if you get your foot in the door early enough at the right company, you could end up a millionaire.
Inspired by a 2012 Quora thread, we decided to come up with our own list of companies you should join if you want to make some serious cash in four years, assuming you're able to negotiate a bunch of stock options when you join.
We've included employee count for each company. For startups whose employee headcounts we didn't have access to from our own reporting, we consulted Pitchbook, a private equity and venture capital database that tracks information about companies.
The companies on this list are blowing up - some are early-stage, some are more mature, but they're all highly valued and fast-growing. You'll want to get hired before they take off further.