diff --git a/src/api/dto/content.rs b/src/api/dto/content.rs
index f451e33..3ef1366 100644
--- a/src/api/dto/content.rs
+++ b/src/api/dto/content.rs
@@ -4,6 +4,7 @@ use std::collections::HashMap;
 
 pub type SsbHash = String;
 pub type SsbId = String;
+pub type SsbMsgType = String;
 
 #[derive(Debug, Serialize, Deserialize)]
 pub struct Mention {
@@ -142,3 +143,22 @@ pub enum TypedMessage {
     #[serde(rename = "vote")]
     Vote { vote: Vote },
 }
+
+//op 	    args name 	args type
+//and 	    args 	[op, ...]
+//or 	    args 	[op, ...]
+//type 	    string 	string
+//author    feed 	string
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(untagged)]
+pub enum SubsetQuery {
+    // {"op":"type","string":"foo"}
+    Type { op: String, string: SsbMsgType },
+    //#[serde(rename = "author")]
+    Author { op: String, feed: SsbId },
+    //#[serde(rename = "and")]
+    //And { args: Vec<SubsetQuery> },
+    //#[serde(rename = "or")]
+    //Or { args: Vec<SubsetQuery> },
+}
diff --git a/src/api/helper.rs b/src/api/helper.rs
index 3401bd3..f1b7584 100644
--- a/src/api/helper.rs
+++ b/src/api/helper.rs
@@ -1,5 +1,5 @@
 use crate::{
-    api::dto::content::TypedMessage,
+    api::dto::content::{SubsetQuery, TypedMessage},
     feed::Message,
     rpc::{Body, BodyType, RequestNo, RpcType, RpcWriter},
 };