diff --git a/dune-project b/dune-project
index f56ce53f..3eed4894 100644
--- a/dune-project
+++ b/dune-project
@@ -39,3 +39,14 @@
     (iostream-camlzip (>= 0.2.1))
     (logs :with-test)
     (odoc :with-doc)))
+
+(package
+  (name tiny_httpd_moonpool)
+  (synopsis "Moonpool+picos_stdio backend for Tiny_httpd")
+  (depends
+    seq
+    (tiny_httpd (= :version))
+    (moonpool (>= 0.7))
+    (moonpool-io (>= 0.7))
+    (ocaml (>= 5.0))
+    (odoc :with-doc)))
diff --git a/src/moonpool-io/dune b/src/moonpool-io/dune
new file mode 100644
index 00000000..f9880adb
--- /dev/null
+++ b/src/moonpool-io/dune
@@ -0,0 +1,6 @@
+
+
+(library
+ (name tiny_httpd_moonpool)
+ (public_name tiny_httpd_moonpool)
+ (libraries tiny_httpd moonpool moonpool.sync moonpool.fib moonpool-io))
diff --git a/src/moonpool-io/io_server.ml b/src/moonpool-io/io_server.ml
new file mode 100644
index 00000000..362511ba
--- /dev/null
+++ b/src/moonpool-io/io_server.ml
@@ -0,0 +1,220 @@
+open Tiny_httpd_core
+module A = Atomic
+module MIO = Moonpool_io
+module Sem = Moonpool_sync.Semaphore.Counting
+module Fd = Moonpool_io.Fd
+
+module IO_helper = struct
+  module Slice = Iostream.Slice
+
+  module Output = struct
+    include IO.Output
+
+    class of_unix_fd ?(close_noerr = false) ~closed ~(buf : Slice.t) (fd : Fd.t) :
+      t =
+      object
+        inherit t_from_output ~bytes:buf.bytes ()
+
+        method private output_underlying bs i len0 =
+          let i = ref i in
+          let len = ref len0 in
+          while !len > 0 do
+            match MIO.Unix.write fd bs !i !len with
+            | 0 -> failwith "write failed"
+            | n ->
+              i := !i + n;
+              len := !len - n
+          done
+
+        method private close_underlying () =
+          if not !closed then (
+            closed := true;
+            if close_noerr then (
+              try MIO.Unix.close fd with _ -> ()
+            ) else
+              MIO.Unix.close fd
+          )
+      end
+  end
+
+  module Input = struct
+    include IO.Input
+
+    let of_unix_fd ?(close_noerr = false) ~closed ~(buf : Slice.t) (fd : Fd.t) :
+        t =
+      let eof = ref false in
+      object
+        inherit Iostream.In_buf.t_from_refill ~bytes:buf.bytes ()
+
+        method private refill (slice : Slice.t) =
+          if not !eof then (
+            slice.off <- 0;
+            let continue = ref true in
+            while !continue do
+              match
+                MIO.Unix.read fd slice.bytes 0 (Bytes.length slice.bytes)
+              with
+              | n ->
+                slice.len <- n;
+                continue := false
+            done;
+            (* Printf.eprintf "read returned %d B\n%!" !n; *)
+            if slice.len = 0 then eof := true
+          )
+
+        method close () =
+          if not !closed then (
+            closed := true;
+            eof := true;
+            if close_noerr then (
+              try MIO.Unix.close fd with _ -> ()
+            ) else
+              MIO.Unix.close fd
+          )
+      end
+  end
+end
+
+open struct
+  let get_addr_ (fd : Fd.t) =
+    match Unix.getsockname (Fd.unsafe_get fd) with
+    | Unix.ADDR_INET (addr, port) -> addr, port
+    | _ -> invalid_arg "httpd: address is not INET"
+
+  let shutdown_silent_ (fd : Fd.t) : unit =
+    try MIO.Unix.shutdown fd Unix.SHUTDOWN_ALL with _ -> ()
+
+  let close_silent_ (fd : Fd.t) : unit = try MIO.Unix.close fd with _ -> ()
+end
+
+type t = {
+  addr: string;
+  port: int;
+  buf_pool: Buf.t Pool.t;
+  slice_pool: IO.Slice.t Pool.t;
+  max_connections: int;
+  sem_max_connections: Sem.t;
+      (** semaphore to restrict the number of active concurrent connections *)
+  mutable sock: Fd.t option;  (** Socket *)
+  new_thread: (unit -> unit) -> unit;
+  timeout: float;
+  running: bool A.t; (* TODO: use an atomic? *)
+}
+
+let to_tcp_server (self : t) : IO.TCP_server.builder =
+  {
+    IO.TCP_server.serve =
+      (fun ~after_init ~handle () : unit ->
+        let sock, should_bind =
+          match self.sock with
+          | Some s ->
+            (* Because we're getting a socket from the caller (e.g. systemd) *)
+            s, false
+          | None ->
+            let sock =
+              Unix.socket
+                (if Util.is_ipv6_str self.addr then
+                  Unix.PF_INET6
+                else
+                  Unix.PF_INET)
+                Unix.SOCK_STREAM 0
+            in
+            let fd = Fd.create sock in
+            fd, true (* Because we're creating the socket ourselves *)
+        in
+        MIO.Unix.clear_nonblock sock;
+        MIO.Unix.setsockopt_optint sock Unix.SO_LINGER None;
+        if should_bind then (
+          let inet_addr = Unix.inet_addr_of_string self.addr in
+          MIO.Unix.setsockopt sock Unix.SO_REUSEADDR true;
+          MIO.Unix.bind sock (Unix.ADDR_INET (inet_addr, self.port));
+          let n_listen = 2 * self.max_connections in
+          MIO.Unix.listen sock n_listen
+        );
+
+        self.sock <- Some sock;
+
+        let tcp_server =
+          {
+            IO.TCP_server.stop = (fun () -> Atomic.set self.running false);
+            running = (fun () -> Atomic.get self.running);
+            active_connections =
+              (fun () ->
+                self.max_connections - Sem.get_value self.sem_max_connections);
+            endpoint =
+              (fun () ->
+                let addr, port = get_addr_ sock in
+                Unix.string_of_inet_addr addr, port);
+          }
+        in
+        after_init tcp_server;
+
+        (* how to handle a single client *)
+        let handle_client_ (client_sock : Fd.t) (client_addr : Unix.sockaddr) :
+            unit =
+          Log.debug (fun k ->
+              k "t[%d]: serving new client on %s"
+                (Thread.id @@ Thread.self ())
+                (Util.show_sockaddr client_addr));
+
+          MIO.Unix.set_nonblock client_sock;
+          MIO.Unix.setsockopt client_sock Unix.TCP_NODELAY true;
+          MIO.Unix.(setsockopt_float client_sock SO_RCVTIMEO self.timeout);
+          MIO.Unix.(setsockopt_float client_sock SO_SNDTIMEO self.timeout);
+
+          Pool.with_resource self.slice_pool @@ fun ic_buf ->
+          Pool.with_resource self.slice_pool @@ fun oc_buf ->
+          let closed = ref false in
+
+          let oc =
+            new IO_helper.Output.of_unix_fd
+              ~close_noerr:true ~closed ~buf:oc_buf client_sock
+          in
+          let ic =
+            IO_helper.Input.of_unix_fd ~close_noerr:true ~closed ~buf:ic_buf
+              client_sock
+          in
+          handle.handle ~client_addr ic oc
+        in
+
+        MIO.Unix.set_nonblock sock;
+        while Atomic.get self.running do
+          match MIO.Unix.accept sock with
+          | client_sock, client_addr ->
+            (* limit concurrency *)
+            Sem.acquire self.sem_max_connections;
+            self.new_thread (fun () ->
+                try
+                  handle_client_ client_sock client_addr;
+                  Log.debug (fun k ->
+                      k "t[%d]: done with client on %s, exiting"
+                        (Thread.id @@ Thread.self ())
+                      @@ Util.show_sockaddr client_addr);
+                  shutdown_silent_ client_sock;
+                  close_silent_ client_sock;
+                  Sem.release self.sem_max_connections
+                with e ->
+                  let bt = Printexc.get_raw_backtrace () in
+                  shutdown_silent_ client_sock;
+                  close_silent_ client_sock;
+                  Sem.release self.sem_max_connections;
+                  Log.error (fun k ->
+                      k
+                        "@[<v>Handler: uncaught exception for client %s:@ %s@ \
+                         %s@]"
+                        (Util.show_sockaddr client_addr)
+                        (Printexc.to_string e)
+                        (Printexc.raw_backtrace_to_string bt)))
+          | exception e ->
+            Log.error (fun k ->
+                k "Unix.accept raised an exception: %s" (Printexc.to_string e));
+            Atomic.set self.running false
+        done;
+
+        (* Wait for all threads to be done: this only works if all threads are done. *)
+        MIO.Unix.close sock;
+        while Sem.get_value self.sem_max_connections < self.max_connections do
+          Sem.acquire self.sem_max_connections
+        done;
+        ());
+  }
diff --git a/src/moonpool-io/tiny_httpd_moonpool.ml b/src/moonpool-io/tiny_httpd_moonpool.ml
new file mode 100644
index 00000000..e432ccec
--- /dev/null
+++ b/src/moonpool-io/tiny_httpd_moonpool.ml
@@ -0,0 +1,52 @@
+include Tiny_httpd
+module Fd = Io_server.Fd
+
+open struct
+  let get_max_connection_ ?(max_connections = 64) () : int =
+    let max_connections = max 4 max_connections in
+    max_connections
+
+  let clear_slice (slice : IO.Slice.t) =
+    Bytes.fill slice.bytes 0 (Bytes.length slice.bytes) '\x00';
+    slice.off <- 0;
+    slice.len <- 0
+end
+
+let create ?max_connections ?(timeout = 0.0) ?buf_size
+    ?(get_time_s = Unix.gettimeofday) ?(addr = "127.0.0.1") ?(port = 8080)
+    ?(sock : Fd.t option) ?middlewares ~(runner : Moonpool.Runner.t) () : t =
+  let new_thread f =
+    ignore (Moonpool_fib.spawn_top ~on:runner f : _ Moonpool_fib.t)
+  in
+  let max_connections = get_max_connection_ ?max_connections () in
+  let server =
+    {
+      Io_server.addr;
+      new_thread;
+      buf_pool =
+        Pool.create ~clear:Buf.clear_and_zero
+          ~mk_item:(fun () -> Buf.create ?size:buf_size ())
+          ();
+      slice_pool =
+        Pool.create ~clear:clear_slice
+          ~mk_item:
+            (let buf_size = Option.value buf_size ~default:4096 in
+             fun () -> IO.Slice.create buf_size)
+          ();
+      running = Atomic.make true;
+      port;
+      sock;
+      max_connections;
+      sem_max_connections = Io_server.Sem.make max_connections;
+      timeout;
+    }
+  in
+  let tcp_server_builder = Io_server.to_tcp_server server in
+  let module B = struct
+    let init_addr () = addr
+    let init_port () = port
+    let get_time_s = get_time_s
+    let tcp_server () = tcp_server_builder
+  end in
+  let backend = (module B : IO_BACKEND) in
+  Server.create_from ?buf_size ?middlewares ~backend ()
diff --git a/tiny_httpd_moonpool.opam b/tiny_httpd_moonpool.opam
new file mode 100644
index 00000000..b067b7d8
--- /dev/null
+++ b/tiny_httpd_moonpool.opam
@@ -0,0 +1,35 @@
+# This file is generated by dune, edit dune-project instead
+opam-version: "2.0"
+version: "0.17"
+synopsis: "Moonpool+picos_stdio backend for Tiny_httpd"
+maintainer: ["c-cube"]
+authors: ["c-cube"]
+license: "MIT"
+homepage: "https://github.com/c-cube/tiny_httpd/"
+bug-reports: "https://github.com/c-cube/tiny_httpd/issues"
+depends: [
+  "dune" {>= "2.9"}
+  "seq"
+  "tiny_httpd" {= version}
+  "moonpool" {>= "0.7"}
+  "moonpool-io" {>= "0.7"}
+  "ocaml" {>= "5.0"}
+  "odoc" {with-doc}
+]
+build: [
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "--promote-install-files=false"
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
+  ["dune" "install" "-p" name "--create-install-files" name]
+]
+dev-repo: "git+https://github.com/c-cube/tiny_httpd.git"