A system and method are provided to implement real-time bidding using instant messaging. In one embodiment, real time messaging may be provided through IM messaging via an IM server over the internet, between a client and a web-based commerce system. The IM server may be provided by various service providers. In another embodiment, real-time messaging between a client and a web-based commerce system may take place over a P2P network provided by a service provider e.g. Skype. The real time messages may include notification messages communicated from the commerce system to a client. A notification message may include an outbid alert message. The real time messages may include re-bid messages communicated from a client to the commerce system.