Is there a website that lists all the ecns and exchanges along with their fees for taking and adding liquidity?
I don't have a fee schedule for all of the ECNS. However, I know that BATS provides the best rebates for adding liquidity.
it would probably be better to find out which ecns you have access to and then look up the fees just for those ones. also, make sure your broker or trading group even passes those fees to you.