diff --git a/src/Tiny_httpd.ml b/src/Tiny_httpd.ml
index 285b62f9..7d62eb1e 100644
--- a/src/Tiny_httpd.ml
+++ b/src/Tiny_httpd.ml
@@ -301,10 +301,20 @@ end
 
 module Headers = struct
   type t = (string * string) list
-  let contains = List.mem_assoc
-  let get ?(f=fun x->x) x h = try Some (List.assoc x h |> f) with Not_found -> None
-  let remove x h = List.filter (fun (k,_) -> k<>x) h
-  let set x y h = (x,y) :: List.filter (fun (k,_) -> k<>x) h
+  let contains name headers =
+    let name' = String.lowercase_ascii name in
+    List.exists (fun (n, _) -> name'=n) headers
+  let get_exn ?(f=fun x->x) x h =
+    let x' = String.lowercase_ascii x in
+    List.assoc x' h |> f
+  let get ?(f=fun x -> x) x h =
+    try Some (get_exn ~f x h) with Not_found -> None
+  let remove x h =
+    let x' = String.lowercase_ascii x in
+    List.filter (fun (k,_) -> k<>x') h
+  let set x y h =
+    let x' = String.lowercase_ascii x in
+    (x',y) :: List.filter (fun (k,_) -> k<>x') h
   let pp out l =
     let pp_pair out (k,v) = Format.fprintf out "@[<h>%s: %s@]" k v in
     Format.fprintf out "@[<v>%a@]" (Format.pp_print_list pp_pair) l
@@ -320,7 +330,7 @@ module Headers = struct
           try Scanf.sscanf line "%s@: %s@\r" (fun k v->k,v)
           with _ -> bad_reqf 400 "invalid header line: %S" line
         in
-        loop ((k,v)::acc)
+        loop ((String.lowercase_ascii k,v)::acc)
       )
     in
     loop []
@@ -444,8 +454,9 @@ module Request = struct
       _debug (fun k->k "got meth: %s, path %S" (Meth.to_string meth) path);
       let headers = Headers.parse_ ~buf bs in
       let host =
-        try List.assoc "Host" headers
-        with Not_found -> bad_reqf 400 "No 'Host' header in request"
+        match Headers.get "Host" headers with
+        | None -> bad_reqf 400 "No 'Host' header in request"
+        | Some h -> h
       in
       Ok (Some {meth; host; path; headers; body=()})
     with
@@ -459,7 +470,7 @@ module Request = struct
   let parse_body_ ~tr_stream ~buf (req:byte_stream t) : byte_stream t resp_result =
     try
       let size =
-        match List.assoc "Content-Length" req.headers |> int_of_string with
+        match Headers.get_exn "Content-Length" req.headers |> int_of_string with
         | n -> n (* body of fixed size *)
         | exception Not_found -> 0
         | exception _ -> bad_reqf 400 "invalid content-length"
@@ -506,6 +517,8 @@ end
   | None -> assert_failure "should parse"
   | Some req ->
     assert_equal (Some "coucou") (Headers.get "Host" req.Request.headers);
+    assert_equal (Some "coucou") (Headers.get "host" req.Request.headers);
+    assert_equal (Some "11") (Headers.get "content-length" req.Request.headers);
     assert_equal "hello" req.Request.path;
     let req = Request.Internal_.parse_body req str |> Request.read_body_full in
     assert_equal ~printer:(fun s->s) "salutations" req.Request.body;