diff --git a/bencode.ml b/bencode.ml
index f9dacd76..e8e220bf 100644
--- a/bencode.ml
+++ b/bencode.ml
@@ -88,7 +88,7 @@ let rec pretty fmt t = match t with
   | S s -> Format.fprintf fmt "@[<h>\"%s\"@]" s
   | L l ->
     Format.fprintf fmt "@[<hov 2>[@,";
-    List.iter (fun t' -> Format.fprintf fmt "%a@ " pretty t') l;
+    List.iteri (fun i t' -> (if i > 0 then Format.pp_print_char fmt ' '); pretty fmt t') l;
     Format.fprintf fmt "]@]";
   | D d ->
     Format.fprintf fmt "@[<hov 2>{@,";
@@ -96,6 +96,12 @@ let rec pretty fmt t = match t with
       (fun k t' -> Format.fprintf fmt "%a -> %a@ " pretty (S k) pretty t')
       d;
     Format.fprintf fmt "}@]";
+    ()
+
+let pretty_to_str t =
+  let b = Buffer.create 15 in
+  Format.fprintf (Format.formatter_of_buffer b) "%a@?" pretty t;
+  Buffer.contents b
 
 (** {2 Deserialization (decoding)} *)
 
diff --git a/bencode.mli b/bencode.mli
index 5e9b64ea..fff1bf0b 100644
--- a/bencode.mli
+++ b/bencode.mli
@@ -52,6 +52,9 @@ val fmt : Format.formatter -> t -> unit
 val pretty : Format.formatter -> t -> unit
   (** Print the tree itself, not its encoding *)
 
+val pretty_to_str : t -> string
+  (** Print the tree into a string *)
+
 (** {2 Deserialization (decoding)} *)
 
 (** Deserialization is based on the {! decoder} type. Parsing can be