diff --git a/core/appmodule/module.go b/core/appmodule/module.go
new file mode 100644
index 000000000000..220dbb06fb32
--- /dev/null
+++ b/core/appmodule/module.go
@@ -0,0 +1,59 @@
+package appmodule
+
+import (
+	"context"
+
+	"cosmossdk.io/depinject"
+	"google.golang.org/grpc"
+)
+
+// AppModule is a tag interface for app module implementations to use as a basis
+// for extension interfaces. It provides no functionality itself, but is the
+// type that all valid app modules should provide so that they can be identified
+// by other modules (usually via depinject) as app modules.
+type AppModule interface {
+	depinject.OnePerModuleType
+
+	// IsAppModule is a dummy method to tag a struct as implementing an AppModule.
+	IsAppModule()
+}
+
+// HasServices is the extension interface that modules should implement to register
+// implementations of services defined in .proto files.
+type HasServices interface {
+	AppModule
+
+	// RegisterServices registers the module's services with the app's service
+	// registrar.
+	//
+	// Two types of services are currently supported:
+	// - read-only gRPC query services, which are the default.
+	// - transaction message services, which must have the protobuf service
+	//   option "cosmos.msg.v1.service" (defined in "cosmos/msg/v1/service.proto")
+	//   set to true.
+	//
+	// The service registrar will figure out which type of service you are
+	// implementing based on the presence (or absence) of protobuf options. You
+	// do not need to specify this in golang code.
+	RegisterServices(grpc.ServiceRegistrar)
+}
+
+// HasBeginBlocker is the extension interface that modules should implement to run
+// custom logic before transaction processing in a block.
+type HasBeginBlocker interface {
+	AppModule
+
+	// BeginBlock is a method that will be run before transactions are processed in
+	// a block.
+	BeginBlock(context.Context) error
+}
+
+// HasEndBlocker is the extension interface that modules should implement to run
+// custom logic after transaction processing in a block.
+type HasEndBlocker interface {
+	AppModule
+
+	// EndBlock is a method that will be run after transactions are processed in
+	// a block.
+	EndBlock(context.Context) error
+}