That is quite good and comparable to IB(investment banker) salaries. Meaning a few years ago $200k by 22, and incrementing $100k a year with $1M by age 30, and $10M by age 40 or so. The starting salaries out of college are now about $350k. My question is I wonder if the upward salary trajectory is similar to that IB track, this is assuming the employee has a somewhat upward career trajectory; does Jane street cap out folks at a certain level?

From my experience, the best way to get a pay increase is to code software for things closer to the trading system. Write code that makes a trading app faster and increases PnL, you'll make more money via bonuses. If you're writing back office code doing data loading, trade reconciliation or other "housekeeping" stuff, you'll not see the same comp.

Because of this, getting a SWE role that is assigned to a trading team is highly desired.