How to set zero commission for backtesting?


I understand that the demo account broker sets the commissions so that when you backtest they are locked in. Is there a way get around this? Are there any brokers that allow you to set zero commission for a backtest?


Many brokers do not have commisions at all. MetaQuotes Demo for example, I believe it doesn't have them.

Those brokers without commisions, normally use high spreads instead. You can backtest setting the spread to 2; so at the end you won't have commisions or spreads)