Vitess V2: Now with more V3
Starting with Vitess v2.0.0-beta.2, the VTGate V3 API can route complex single-shard queries (containing joins, subqueries, aggregation, sorting, and any combination thereof) as well as perform cross-shard joins. That means you no longer need to tell VTGate the keyspace ID that a query targets, as you did with the VTGate V2 API.
The fact that keyspace IDs are now hidden from the application has enabled drop-in Vitess libraries for standard database interfaces like JDBC (written by Flipkart), PDO (written by Pixel Federation), PEP 249, and database/sql.