diff --git a/src/sfizz.h b/src/sfizz.h
index 5e5c6af8..36f6216d 100644
--- a/src/sfizz.h
+++ b/src/sfizz.h
@@ -394,6 +394,25 @@ SFIZZ_EXPORTED_API void sfizz_set_logging_prefix(sfizz_synth_t* synth, const cha
  */
 SFIZZ_EXPORTED_API void sfizz_all_sound_off(sfizz_synth_t* synth);
 
+/**
+ * @brief Add external definitions prior to loading;
+ * Note that these do not get reset by loading or resetting the synth.
+ * You need to call sfizz_clear_external_definitions() to erase them.
+ *
+ * @param synth
+ * @param id
+ * @param value
+ */
+SFIZZ_EXPORTED_API void sfizz_add_external_definitions(sfizz_synth_t* synth, const char* id, const char* value);
+
+/**
+ * @brief Clears external definitions for the next file loading.
+ *
+ * @param synth
+ */
+SFIZZ_EXPORTED_API void sfizz_clear_external_definitions(sfizz_synth_t* synth);
+
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/sfizz.hpp b/src/sfizz.hpp
index d0e62e37..911b5eac 100644
--- a/src/sfizz.hpp
+++ b/src/sfizz.hpp
@@ -284,6 +284,21 @@ public:
      *
      */
     void allSoundOff() noexcept;
+
+    /**
+     * @brief Add external definitions prior to loading;
+     * Note that these do not get reset by loading or resetting the synth.
+     * You need to call clearExternalDefintions() to erase them.
+     *
+     * @param id
+     * @param value
+     */
+    void addExternalDefinition(const std::string& id, const std::string& value);
+    /**
+     * @brief Clears external definitions for the next file loading.
+     *
+     */
+    void clearExternalDefinitions();
 private:
     std::unique_ptr<sfz::Synth> synth;
 };
diff --git a/src/sfizz/sfizz.cpp b/src/sfizz/sfizz.cpp
index 08f88c1a..3e17af01 100644
--- a/src/sfizz/sfizz.cpp
+++ b/src/sfizz/sfizz.cpp
@@ -210,3 +210,13 @@ void sfz::Sfizz::allSoundOff() noexcept
 {
     synth->allSoundOff();
 }
+
+void sfz::Sfizz::addExternalDefinition(const std::string& id, const std::string& value)
+{
+    synth->getParser().addExternalDefinition(id, value);
+}
+
+void sfz::Sfizz::clearExternalDefinitions()
+{
+    synth->getParser().clearExternalDefinitions();
+}
diff --git a/src/sfizz/sfizz_wrapper.cpp b/src/sfizz/sfizz_wrapper.cpp
index bc62c4c7..3c9d88f0 100644
--- a/src/sfizz/sfizz_wrapper.cpp
+++ b/src/sfizz/sfizz_wrapper.cpp
@@ -256,6 +256,18 @@ void sfizz_all_sound_off(sfizz_synth_t* synth)
     return self->allSoundOff();
 }
 
+void sfizz_add_external_definitions(sfizz_synth_t* synth, const char* id, const char* value)
+{
+    auto self = reinterpret_cast<sfz::Synth*>(synth);
+    self->getParser().addExternalDefinition(id, value);
+}
+
+void sfizz_clear_external_definitions(sfizz_synth_t* synth)
+{
+    auto self = reinterpret_cast<sfz::Synth*>(synth);
+    self->getParser().clearExternalDefinitions();
+}
+
 #ifdef __cplusplus
 }
 #endif