I'm going to assume you are young, unmarried, good technically, but have not run your own business before.
I'd set aside four months of your current living expenses, and keep it in the bank for emergencies. Having something like this just takes a lot of the stress out of life.
Secondly, I'd set aside about $10,000 into a separate bank account and use small amounts (sub $100) to encourage other people towards their dreams, or help them over bumps in the road. (See https://news.ycombinator.com/item?id=14500784)
If you want to try your own startup with $20,000 go for it, but set a limit on how much of your own money you will spend before profitability. Sometimes during gold rushes, it's more profitable to sell picks and pants than mine for gold. Whatever you are currently doing sounds pretty lucrative, and might have a higher expected value.
Lastly I'd put the rest is long term Vanguard index funds. It only takes $1,000,000 to retire to an upper-middle class lifestyle in the nice-but-not-expensive parts of the US. This would put you well on your way there.
The best part about having money "in the bank" is that it allows you to leave bad employers and bad contracts without fear, which allows you to spend your life working with good people who pay well.