A distributed system that implements an online exchange may comprise a plurality of server nodes, each of which being configured to receive exchange transaction proposals from customers of the online exchange over a computer network and each being configured to store a copy of a blockchain distributed ledger of completed exchange transactions. A consensus engine may be coupled, over the computer network, to the plurality of server nodes and may receive a plurality of exchange transaction proposals from the plurality of server nodes. The consensus engine may be being further configured to achieve consensus on the plurality of exchange transaction proposals and to generate, in response, an ordering of agreed-upon exchange transaction proposals that includes the plurality of exchange transaction proposals on which consensus has been reached. This ordering of agreed-upon exchange transaction proposals is identically provided to each of the server nodes and specifies the order in which the server nodes are to execute exchange transactions and to update their copy of the distributed ledger. The ordering of agreed-upon exchange transaction proposals may optionally be re-ordered and identically provided to each server node to conform to the local orderings at the exchange transaction proposal's node server of origin.