diff --git a/exercises/practice/circular-buffer/circular_buffer.h b/exercises/practice/circular-buffer/circular_buffer.h
index 9f809d42c..ec13e26d0 100644
--- a/exercises/practice/circular-buffer/circular_buffer.h
+++ b/exercises/practice/circular-buffer/circular_buffer.h
@@ -1,4 +1,30 @@
 #ifndef CIRCULAR_BUFFER_H
 #define CIRCULAR_BUFFER_H
 
+#include <stddef.h>
+#include <stdint.h>
+
+typedef int16_t buffer_value_t;
+typedef struct circular_buffer_t circular_buffer_t;
+
+// constructs a new buffer
+circular_buffer_t *new_circular_buffer(size_t capacity);
+
+// read next value from buffer
+int16_t read(circular_buffer_t *buffer, buffer_value_t *value);
+
+// write a value to the buffer
+int16_t write(circular_buffer_t *buffer, buffer_value_t value);
+
+// write a value to the buffer
+// overwrites the oldest value if the buffer is already full
+int16_t overwrite(circular_buffer_t *buffer, buffer_value_t value);
+
+// clear the buffer
+void clear_buffer(circular_buffer_t *buffer);
+
+// destroy the entire buffer
+// buffer will be a dangling pointer after calling this method on it
+void delete_buffer(circular_buffer_t *buffer);
+
 #endif