diff --git a/userspace/engine/json_evt.cpp b/userspace/engine/json_evt.cpp
index 50f643d3..61cdc90d 100644
--- a/userspace/engine/json_evt.cpp
+++ b/userspace/engine/json_evt.cpp
@@ -45,7 +45,7 @@ const json &json_event::jevt()
 	return m_jevt;
 }
 
-uint64_t json_event::get_ts()
+uint64_t json_event::get_ts() const
 {
 	return m_event_ts;
 }
diff --git a/userspace/engine/json_evt.h b/userspace/engine/json_evt.h
index 9c32cc8c..34d59aec 100644
--- a/userspace/engine/json_evt.h
+++ b/userspace/engine/json_evt.h
@@ -38,14 +38,14 @@ public:
 	void set_jevt(nlohmann::json &evt, uint64_t ts);
 	const nlohmann::json &jevt();
 
-	uint64_t get_ts();
+	uint64_t get_ts() const;
 
-	inline uint16_t get_source()
+	inline uint16_t get_source() const
 	{
 		return ESRC_K8S_AUDIT;
 	}
 
-	inline uint16_t get_type()
+	inline uint16_t get_type() const
 	{
 		// All k8s audit events have the single tag "1". - see falco_engine::process_k8s_audit_event
 		return 1;