If the data source can be exposed through an HTTP interface or JSON stream it can probably already be integrated. The real problem is with object-relation mapping (ORM) layers, which Meteor doesn't support. Keep in mind that Meteor's performance and functionality is very much related to not having the overhead of an ORM layer, so it's something that people are reluctant to add in. But if the enterprise system can take care of the ORM mapping and generate a stream of JSON objects, Meteor can consume that a couple of different ways (i.e. directly into the Mongo database, and use Mongo as a persistent object store/caching layer, or directly to minimongo on the client side.