Real-time bidding (RTB) is a type of programmatic media buying where mobile ad impressions are bought and sold automatically in real time. While publishers set floor prices and requirements for ad places, advertisers define their target audiences and bids accordingly.

There are 3 different parties involved in Real Time Bidding: 

• Demand-Side Platform (DSP): Consists of mobile advertisers from agencies to mobile ad networks who want to buy and manage multiple ad spaces without wasting time and money.
  Learn more about Demand-Side Platforms  
  
  
• Supply-Side Platform (SSP): Consists of publishers who want to sell pre-determined ad spaces within their mobile apps to mobile advertisers.
  Learn more about Supply-Side Platforms
  
  
• Ad Exchanges: Online marketplaces where advertisers and publishers buy and sell ad spaces automatically. There are two different kinds of ad exchanges. open exchanges or private exchanges. While open exchanges are open to everyone, the private exchanges are for the publishers who want to know who to sell and at what price.
  Learn more about Ad Exchanges