diff --git a/lib/src/tsetlini_state_json.cpp b/lib/src/tsetlini_state_json.cpp
index a861c4b..eb8c583 100644
--- a/lib/src/tsetlini_state_json.cpp
+++ b/lib/src/tsetlini_state_json.cpp
@@ -283,6 +283,9 @@ std::string to_json_string(ClassifierStateClassic const & state)
 {
     json js;
 
+    js["estimator"] = "classifier";
+    js["algo"] = "classic";
+
     js["ta_state"] = state.ta_state;
     js["igen"] = state.igen;
     js["fgen"] = state.fgen;
@@ -325,6 +328,9 @@ std::string to_json_string(RegressorStateClassic const & state)
 {
     json js;
 
+    js["estimator"] = "regressor";
+    js["algo"] = "classic";
+
     js["ta_state"] = state.ta_state;
     js["igen"] = state.igen;
     js["fgen"] = state.fgen;
@@ -367,6 +373,9 @@ std::string to_json_string(RegressorStateBitwise const & state)
 {
     json js;
 
+    js["estimator"] = "regressor";
+    js["algo"] = "bitwise";
+
     js["ta_state"] = state.ta_state;
     js["igen"] = state.igen;
     js["fgen"] = state.fgen;
@@ -409,6 +418,9 @@ std::string to_json_string(ClassifierStateBitwise const & state)
 {
     json js;
 
+    js["estimator"] = "classifier";
+    js["algo"] = "bitwise";
+
     js["ta_state"] = state.ta_state;
     js["igen"] = state.igen;
     js["fgen"] = state.fgen;