Building distributed systems is notoriously difficult. Although techniques such as vector clocks make writing correct software more tractable, they are themselves very tricky to work with. The Riak decentralized key-value store is one of the best known open source systems that uses vector clocks. We have developed a Haskell client for Riak. Our client uses Haskell's type system to optionally make the use of vector clocks transparent, allowing the application programmer to concentrate on their business logic.

We will talk about the design considerations for our client, how we use types, and what factors we believe are important in building solid distributed applications.