Skip to main content
Version: v2.x

Read Replicas


Hasura Cloud and Hasura Enterprise can route queries and subscriptions across read replicas while sending all mutations and Metadata API calls to the primary.

This works by selecting a read replica instance at random. Hasura does not perform any kind of load balancing across the replicas. The random function used has a uniform distribution, and so over time, queries will distribute uniformly across all replica instances.

Adding read replica URLs


Head to Data -> Manage -> <db-name> -> Edit

Connect database with read replica
For existing v1.3 projects

If you have configured your Postgres instances with replicas; then the replica URLs can be added to Hasura using the following environment variable in your project ENV Vars tab:


In the case of multiple replicas, you can add the URLs of each replica as comma-separated values.

Additional environment variables for read replicas specifically:



NOTE: Please note that the above environment variables are only available for v1.3 projects and are no longer supported for v2.0 and above projects.

MS SQL Server

Head to Data -> Manage -> <db-name> -> Edit

Connect database with read replica