Buttercoin is an open source, high-volume trading engine used to arrange trades in an order book. It's inspired by the architecture of LMAX and aspires to very high throughput while remaining agnostic of what is traded. Current exchanges such as MtGox and Bitstamp have run into problems when handling high amounts of load. Buttercoin would let exchange operators run a high performance trading platform while separating out other concerns (like websocket tickers) that have different scaling characteristics.
