--- a/docs/Writerside/topics/json.h.md	Sun Dec 07 13:18:22 2025 +0100
+++ b/docs/Writerside/topics/json.h.md	Sun Dec 07 13:24:18 2025 +0100
@@ -7,6 +7,13 @@
 
 ## Parser
 
+The following listing shows the JSON parser API.
+
+> To simplify documentation, we introduce the pseudo-type `AnyStr` with the meaning that
+> any UCX string and any C string are supported.
+> The implementation is actually hidden behind a macro which uses `cx_strcast()` to guarantee compatibility.
+{style="note"}
+
 ```C
 #include <cx/json.h>