You can work with more than one Ad Network at once. Splitting your ad inventory and working with more than one Ad Network can get your fill rate up to 100%, maximizing your revenues, but you might spend a lot of time managing them.
My recommendation is to try a mediation solution like Fyber, Tappx, Ironsource, Appodeal… Basically these services connect in real time, with hundreds of demand sources in the search of the highest paid ad for you. They do the dirty job and you only focus on coding
Bonus track: Tappx also get users for FREE for your app/game because of their cross-promotion app developer community
My recommendation is to try a mediation solution like Fyber, Tappx, Ironsource, Appodeal… Basically these services connect in real time, with hundreds of demand sources in the search of the highest paid ad for you. They do the dirty job and you only focus on coding
Bonus track: Tappx also get users for FREE for your app/game because of their cross-promotion app developer community