Data is everywhere and is usually stored across multiple databases and data sources. Different teams in an organization might have their own database. Different types of workloads could mean that you have specialised databases for specialised use cases. In enterprises there is often a mix of legacy databases as well as modern ones. We introduced Remote Joins last year to join across databases and remote GraphQL servers. With Cross Databases Joins at the API layer, we have taken Remote Joins to the next level. All you have to do is configure Hasura to connect to your databases and, with no upstream changes to the underlying database, you can start querying across them! With a single GraphQL query, Hasura will let you fetch related data from multiple databases with authorization baked in. Hasura federates the GraphQL request to the underlying databases giving you the experience of all the data being in a single database! In this talk, Tanmai Gopal does a deep dive into this feature.