diff --git a/SUMMARY.md b/SUMMARY.md
index 6ae71fc..2d52d4e 100644
--- a/SUMMARY.md
+++ b/SUMMARY.md
@@ -73,7 +73,8 @@
         * [Core Models](xos/core_models.md)
         * [Security Policies](xos/security_policies.md)
         * [Tutorial](xos/tutorials/basic_synchronizer.md)
-        * [Build proto files from xProto](xos/dev/xproto_to_protobuf.md)
+    * [API Interaction](api/api.md)
+        * [gRPC API Tutorial](xos/dev/grpc_api.md)
     * [Developer Workflows](developer/workflows.md)
         * [Working on R-CORD Without an OLT/ONU](developer/configuration_rcord.md)
     * [Building Docker Images](developer/imagebuilder.md)
diff --git a/api/api.md b/api/api.md
new file mode 100644
index 0000000..1f5574a
--- /dev/null
+++ b/api/api.md
@@ -0,0 +1,12 @@
+# API Interaction
+
+This guide describes workflows for interacting with the API of the NEM. There
+are several different API mechanisms that the NEM supports. Some of them are
+used in a Northbound context, for services sitting on top the NEM to interact
+with the NEM, and some are used internally for components to communicate with each other.
+
+* [gRPC](/xos/dev/grpc_api.md). The gRPC API is used internally for synchronizers and for Chameleon to speak with the XOS core. It's also available as a Northbound API.
+
+* REST. The REST API is implemented by the Chameleon container. In addition to being a popular Northbound API, it's also used by the XOS GUI.
+
+* Tosca. TOSCA is implemented by the xos-tosca container. TOSCA is used extensively in bootstrapping the system, and can also be used as a general-purpose runtime API.