diff --git a/fortran/eccodes_f90_tail.f90 b/fortran/eccodes_f90_tail.f90
index c2df8fdb8..9df0095e5 100644
--- a/fortran/eccodes_f90_tail.f90
+++ b/fortran/eccodes_f90_tail.f90
@@ -35,10 +35,12 @@ end subroutine codes_set_missing
 !>
 !> \b Examples: \ref grib_index.f90 "grib_index.f90"
 !>
-!> @param indexid     id of the newly created index
-!> @param filename    name of the file of messages to be indexed
-!> @param keys        : comma separated list of keys for the index. The type of the key can be explicitly declared appending :l for long, :d for double, :s for string to the key name. If the type is not declared explicitly, the native type is assumed.
-!> @param status      CODES_SUCCESS if OK, integer value on error
+!> @param indexid   id of the newly created index
+!> @param filename  name of the file of messages to be indexed
+!> @param keys      comma separated list of keys for the index.
+!>                  The type of the key can be explicitly declared appending :l for long (or alternatively :i), :d for double, :s for string to the key name.
+!>                  If the type is not declared explicitly, the native type is assumed.
+!> @param status    CODES_SUCCESS if OK, integer value on error
 subroutine codes_index_create ( indexid, filename, keys,  status )
     integer(kind=kindOfInt),         intent(inout)  :: indexid
     character(len=*), intent(in)                    :: filename
diff --git a/python/gribapi/gribapi.py b/python/gribapi/gribapi.py
index ee8fec3a9..4b2303344 100644
--- a/python/gribapi/gribapi.py
+++ b/python/gribapi/gribapi.py
@@ -1009,7 +1009,8 @@ def grib_index_new_from_file(filename, keys):
     \b Examples: \ref grib_index.py "grib_index.py"
 
     @param filename   path of the file to index on
-    @param keys       sequence of keys to index on
+    @param keys       sequence of keys to index on.
+                      The type of the key can be explicitly declared appending :l for long (or alternatively :i), :d for double, :s for string to the key name.
     @return index id
     @exception GribInternalError
     """
diff --git a/src/eccodes.h b/src/eccodes.h
index 1af74747e..a169f831d 100644
--- a/src/eccodes.h
+++ b/src/eccodes.h
@@ -202,6 +202,7 @@ typedef struct grib_index             codes_index;
  * @param filename    : name of the file of messages to be indexed
  * @param keys        : comma separated list of keys for the index.
  *    The type of the key can be explicitly declared appending :l for long,
+ *    (or alternatively :i)
  *    :d for double, :s for string to the key name. If the type is not
  *    declared explicitly, the native type is assumed.
  * @param err         :  0 if OK, integer value on error
@@ -215,6 +216,7 @@ codes_index* codes_index_new_from_file(codes_context* c, char* filename,const ch
  * @param c           : context  (NULL for default context)
  * @param keys        : comma separated list of keys for the index.
  *    The type of the key can be explicitly declared appending :l for long,
+ *    (or alternatively :i)
  *    :d for double, :s for string to the key name. If the type is not
  *    declared explicitly, the native type is assumed.
  * @param err         :  0 if OK, integer value on error
diff --git a/src/grib_api.h b/src/grib_api.h
index 460df9428..520a384d1 100644
--- a/src/grib_api.h
+++ b/src/grib_api.h
@@ -247,6 +247,7 @@ typedef struct grib_index grib_index;
  * @param filename    : name of the file of messages to be indexed
  * @param keys        : comma separated list of keys for the index.
  *    The type of the key can be explicitly declared appending :l for long,
+ *    (or alternatively :i)
  *    :d for double, :s for string to the key name. If the type is not
  *    declared explicitly, the native type is assumed.
  * @param err         :  0 if OK, integer value on error
@@ -260,6 +261,7 @@ grib_index* grib_index_new_from_file(grib_context* c,
  * @param c           : context  (NULL for default context)
  * @param keys        : comma separated list of keys for the index.
  *    The type of the key can be explicitly declared appending :l for long,
+ *    (or alternatively :i)
  *    :d for double, :s for string to the key name. If the type is not
  *    declared explicitly, the native type is assumed.
  * @param err         :  0 if OK, integer value on error