Transaction processing using a key-value store

Techniques are described for using a distributed key-value store to store data and track transactions performed against the data. The key-value store may include data objects as files in a file system, such that the file name of a file is a key and the contents of the file is a value corresponding to the key. The key-value store may also include transaction objects that track the status of transactions to modify the data objects, the status being one of open, committed, or cancelled. Previous and updated data may be included in the value of a data object to indicate that the data object is in the process of being modified. The value may also include a transaction identifier identifying the transaction that is modifying the data object.