diff --git a/src/unix/async_io.ml b/src/unix/async_io.ml
index 0d8c944e..302803c1 100644
--- a/src/unix/async_io.ml
+++ b/src/unix/async_io.ml
@@ -1,5 +1,6 @@
 open Common_
 module Slice = Iostream_types.Slice
+module Fut = Moonpool.Fut
 
 let rec read (fd : Fd.t) buf i len : int =
   if len = 0 || Fd.closed fd then
@@ -145,9 +146,13 @@ module TCP_server = struct
     method running : unit -> bool
     method run : unit -> unit
     method stop : unit -> unit
+    method await : unit -> unit
   end
 
-  let run (self : #t) = self#run ()
+  let[@inline] run (self : #t) = self#run ()
+  let[@inline] stop (self : #t) = self#stop ()
+  let[@inline] endpoint (self : #t) = self#endpoint ()
+  let[@inline] await (self : #t) = self#await ()
 
   type state =
     | Created
@@ -166,12 +171,19 @@ module TCP_server = struct
     t =
     let n_active_ = A.make 0 in
     let st = A.make Created in
+    let fut, promise = Fut.make () in
 
     object
       method endpoint () = addr
       method active_connections () = A.get n_active_
       method running () = A.get st = Running
-      method stop () = if A.exchange st Stopped = Running then ( (* TODO *) )
+
+      method stop () =
+        match A.exchange st Stopped with
+        | Stopped -> ()
+        | Created | Running -> Fut.fulfill_idempotent promise @@ Ok ()
+
+      method await () = Fut.await fut
 
       method run () =
         (* set to Running *)
@@ -196,8 +208,10 @@ module TCP_server = struct
               Unix.listen sock listen;
               sock
             with e ->
+              let bt = Printexc.get_raw_backtrace () in
               A.set st Stopped;
-              raise e
+              Fut.fulfill_idempotent promise @@ Error (Exn_bt.make e bt);
+              Printexc.raise_with_backtrace e bt
           in
           while A.get st = Running do
             let client_sock, client_addr = accept_ sock in
@@ -233,6 +247,15 @@ module TCP_server = struct
     in
     after_init self;
     self
+
+  let with_server ?listen ?buf_pool ?buf_size ~runner ~handle addr (f : _ -> 'a)
+      : 'a =
+    let server =
+      new base_server ?listen ?buf_pool ?buf_size ~runner ~handle addr
+    in
+    run server;
+    let@ () = Fun.protect ~finally:(fun () -> stop server) in
+    f server
 end
 
 module TCP_client = struct
diff --git a/src/unix/async_io.mli b/src/unix/async_io.mli
index f044ee3f..af164ef9 100644
--- a/src/unix/async_io.mli
+++ b/src/unix/async_io.mli
@@ -84,8 +84,16 @@ module TCP_server : sig
     method stop : unit -> unit
     (** Ask the server to stop. This might not take effect immediately,
       and is idempotent. After this [server.running()] must return [false]. *)
+
+    method await : unit -> unit
+    (** Wait for the server to stop running *)
   end
 
+  val stop : #t -> unit
+  val run : #t -> unit
+  val endpoint : #t -> Sockaddr.t
+  val await : #t -> unit
+
   class base_server :
     ?listen:int ->
     ?buf_pool:Buf_pool.t ->
@@ -105,5 +113,13 @@ module TCP_server : sig
     Sockaddr.t ->
     t
 
-  val run : #t -> unit
+  val with_server :
+    ?listen:int ->
+    ?buf_pool:Buf_pool.t ->
+    ?buf_size:int ->
+    runner:Moonpool.Runner.t ->
+    handle:conn_handler ->
+    Sockaddr.t ->
+    (t -> 'a) ->
+    'a
 end
diff --git a/src/unix/ev_loop.ml b/src/unix/ev_loop.ml
index 66623a40..8c265d9d 100644
--- a/src/unix/ev_loop.ml
+++ b/src/unix/ev_loop.ml
@@ -222,50 +222,34 @@ end
 
 let current_ : Ev_loop.t option A.t = A.make None
 
-let rec set_as_current_ (ev : Ev_loop.t) : bool =
+let rec get_or_set_as_current_ (ev : Ev_loop.t) : Ev_loop.t * bool =
   match A.get current_ with
-  | Some _ -> false
+  | Some ev -> ev, false
   | None ->
     if A.compare_and_set current_ None (Some ev) then
-      true
+      ev, true
     else
-      set_as_current_ ev
+      get_or_set_as_current_ ev
 
-let with_loop ~runner f =
-  let@ _sp = Tracing_.with_span "Moonpool_unix.main" in
-
-  let ev_loop = Ev_loop.create () in
-  if not (set_as_current_ ev_loop) then
-    failwith "Moonpool_unix: the event loop is already active";
-
-  (* schedule [f] on the pool *)
-  let fib = Fiber.spawn_top ~on:runner f in
-
-  while not (Fiber.is_done fib) do
+let bg_loop_ (ev_loop : Ev_loop.t) =
+  let@ _sp = Tracing_.with_span "Moonpool_unix.bg-loop" in
+  while true do
     Ev_loop.run_step_ ev_loop
-  done;
-  A.set current_ None;
+  done
 
-  (* return result of [fib] *)
-  Moonpool.Fut.get_or_fail_exn @@ Fiber.res fib
-
-let start_background_loop () =
-  let run () =
-    let@ _sp = Tracing_.with_span "Moonpool_unix.bg-loop" in
-    let ev_loop = Ev_loop.create () in
-    if set_as_current_ ev_loop then
-      while true do
-        Ev_loop.run_step_ ev_loop
-      done
-  in
-  ignore (Thread.create run () : Thread.t)
+let[@inline never] start_background_loop () : Ev_loop.t =
+  let ev_loop = Ev_loop.create () in
+  let ev_loop, we_are_it = get_or_set_as_current_ ev_loop in
+  (* start the background thread *)
+  if we_are_it then ignore (Thread.create bg_loop_ ev_loop : Thread.t);
+  ev_loop
 
 (* ### external inputs *)
 
 let[@inline] get_current_ () =
   match A.get current_ with
-  | None -> failwith "Moonpool_unix: event loop is not active"
   | Some ev -> ev
+  | None -> start_background_loop ()
 
 let interrupt_if_in_blocking_section_ (self : Ev_loop.t) =
   if A.get self.in_blocking_section then (
diff --git a/src/unix/ev_loop.mli b/src/unix/ev_loop.mli
index 48bab911..4f0e1ebe 100644
--- a/src/unix/ev_loop.mli
+++ b/src/unix/ev_loop.mli
@@ -8,11 +8,3 @@ val wait_writable :
 
 val run_after_s : float -> Cancel_handle.t -> (Cancel_handle.t -> unit) -> unit
 val run_every_s : float -> Cancel_handle.t -> (Cancel_handle.t -> unit) -> unit
-
-val with_loop : runner:Moonpool.Runner.t -> (unit -> 'a) -> 'a
-(** Run with the event loop processed in the current thread. There can
-   only be one such loop running at a time.
-   @raise Failure if another call to {!with_loop} is already in effect. *)
-
-val start_background_loop : unit -> unit
-(** Start the event loop in a new background thread. Idempotent. *)
diff --git a/src/unix/moonpool_unix.ml b/src/unix/moonpool_unix.ml
index ca87a3f3..cde342f2 100644
--- a/src/unix/moonpool_unix.ml
+++ b/src/unix/moonpool_unix.ml
@@ -12,8 +12,9 @@ module Fut = Moonpool.Fut
 
 module Fd = Fd
 module Cancel_handle = Cancel_handle
+module Sockaddr = Sockaddr
 include Async_io
 
 let run_after_s = Ev_loop.run_after_s
 let run_every_s = Ev_loop.run_every_s
-let main = Ev_loop.with_loop
+let main = Moonpool_fib.main
diff --git a/src/unix/sockaddr.ml b/src/unix/sockaddr.ml
index 6089cefd..3f7958ac 100644
--- a/src/unix/sockaddr.ml
+++ b/src/unix/sockaddr.ml
@@ -5,6 +5,10 @@ let show = function
   | Unix.ADDR_INET (addr, port) ->
     Printf.sprintf "%s:%d" (Unix.string_of_inet_addr addr) port
 
+let unix str : t = Unix.ADDR_UNIX str
+let inet addr port : t = Unix.ADDR_INET (addr, port)
+let localhost port : t = inet Unix.inet_addr_loopback port
+let any port : t = inet Unix.inet_addr_any port
 let pp out (self : t) = Format.pp_print_string out (show self)
 
 let domain = function
diff --git a/test/unix/dune b/test/unix/dune
index 9bd54ad2..8098a9e9 100644
--- a/test/unix/dune
+++ b/test/unix/dune
@@ -1,3 +1,4 @@
 (executables
  (names t_hash echo_server)
- (libraries moonpool moonpool.unix trace.core trace-tef))
+ ;(package moonpool-unix)
+ (libraries moonpool moonpool-unix trace.core trace-tef))
diff --git a/test/unix/echo_server.ml b/test/unix/echo_server.ml
index e9e0426e..12683bb0 100644
--- a/test/unix/echo_server.ml
+++ b/test/unix/echo_server.ml
@@ -3,44 +3,49 @@ module MU = Moonpool_unix
 module Trace = Trace_core
 
 let ( let@ ) = ( @@ )
-let spf = Printf.sprintf
-
-let str_of_sockaddr = function
-  | Unix.ADDR_UNIX s -> s
-  | Unix.ADDR_INET (addr, port) ->
-    spf "%s:%d" (Unix.string_of_inet_addr addr) port
 
 let main ~port ~j () : unit =
   let@ _sp = Trace.with_span ~__FILE__ ~__LINE__ "main" in
   let@ runner = M.Ws_pool.with_ ~name:"tpool" ~num_threads:j () in
 
-  let@ () = MU.main ~runner in
+  let@ _main_runner = MU.main in
   Trace.set_thread_name "main";
   Printf.printf "IN MAIN\n%!";
+  Trace.message "foo1";
 
-  MU.TCP_server.with_server ~port ~runner ()
-    ~after_init:(fun self ->
-      Printf.printf "listening on port %d\n%!" (MU.TCP_server.port self))
-    ~handle_client:(fun _server addr ic oc ->
-      let@ _sp =
-        Trace.with_span ~__FILE__ ~__LINE__ "handle.client" ~data:(fun () ->
-            [ "addr", `String (str_of_sockaddr addr) ])
-      in
+  let@ server =
+    MU.TCP_server.with_server ~runner (MU.Sockaddr.any port)
+      ~handle:(fun ~client_addr:addr ic oc ->
+        Trace.message "got new client";
+        let@ _sp =
+          Trace.with_span ~__FILE__ ~__LINE__ "handle.client" ~data:(fun () ->
+              [ "addr", `String (MU.Sockaddr.show addr) ])
+        in
 
-      let buf = Bytes.create 32 in
-      let continue = ref true in
-      while !continue do
-        Trace.message "read";
-        let n = MU.IO_in.input ic buf 0 (Bytes.length buf) in
-        if n = 0 then continue := false;
-        Trace.messagef (fun k -> k "got %dB" n);
-        MU.IO_out.output oc buf 0 n;
-        MU.IO_out.flush oc;
-        Trace.message "write"
-        (* MU.sleep_s 0.02 *)
-      done)
+        let buf = Bytes.create 32 in
+        let continue = ref true in
+        while !continue do
+          Trace.message "read";
+          let n = Iostream.In_buf.input ic buf 0 (Bytes.length buf) in
+          if n = 0 then continue := false;
+          Trace.messagef (fun k -> k "got %dB" n);
+          Iostream.Out_buf.output oc buf 0 n;
+          Iostream.Out_buf.flush oc;
+          Trace.message "write"
+          (* MU.sleep_s 0.02 *)
+        done)
+  in
+
+  Trace.messagef (fun k ->
+      k "server established on %s"
+        (MU.Sockaddr.show @@ MU.TCP_server.endpoint server));
+  Printf.printf "listening on %s\n%!"
+    (MU.Sockaddr.show @@ MU.TCP_server.endpoint server);
+  MU.TCP_server.await server;
+  ()
 
 let () =
+  Sys.catch_break true;
   let@ () = Trace_tef.with_setup () in
   Trace.set_thread_name "entry";
   let port = ref 0 in