diff --git a/apis/installer/v1alpha1/ace_ace_types.go b/apis/installer/v1alpha1/ace_ace_types.go
index 35c037c5a..aec308a13 100644
--- a/apis/installer/v1alpha1/ace_ace_types.go
+++ b/apis/installer/v1alpha1/ace_ace_types.go
@@ -188,6 +188,8 @@ type AceOpenfga struct {
 // shadows the inlined OpenfgaSpec.Datastore so that ace/values.yaml only
 // carries these knobs instead of the full upstream datastore schema.
 type AceOpenfgaDatastore struct {
+	// +optional
+	Engine string `json:"engine"`
 	// +optional
 	MaxOpenConns string `json:"maxOpenConns,omitempty"`
 	// +optional
diff --git a/charts/ace/README.md b/charts/ace/README.md
index 7c3b205b3..1e99dd347 100644
--- a/charts/ace/README.md
+++ b/charts/ace/README.md
@@ -65,6 +65,7 @@ The following table lists the configurable parameters of the `ace` chart and the
 | s3proxy.enabled                                      |                                                                                                                                                                                                                                                | <code>false</code>                                                                                                                                                                             |
 | openfga.enabled                                      |                                                                                                                                                                                                                                                | <code>false</code>                                                                                                                                                                             |
 | openfga.datastoreURI                                 |                                                                                                                                                                                                                                                | <code>""</code>                                                                                                                                                                                |
+| openfga.datastore.engine                             |                                                                                                                                                                                                                                                | <code>postgres</code>                                                                                                                                                                          |
 | openfga.datastore.maxOpenConns                       |                                                                                                                                                                                                                                                | <code>"20"</code>                                                                                                                                                                              |
 | openfga.datastore.connMaxIdleTime                    |                                                                                                                                                                                                                                                | <code>"10m"</code>                                                                                                                                                                             |
 | pgoutbox.enabled                                     |                                                                                                                                                                                                                                                | <code>false</code>                                                                                                                                                                             |
diff --git a/charts/ace/values.yaml b/charts/ace/values.yaml
index 9cfd8aec9..1b50cddc0 100644
--- a/charts/ace/values.yaml
+++ b/charts/ace/values.yaml
@@ -80,6 +80,7 @@ openfga:
   enabled: false
   datastoreURI: ""
   datastore:
+    engine: postgres
     maxOpenConns: "20"
     connMaxIdleTime: "10m"
   ## configured in lib-selfhost