diff --git a/src/client-ocurl-lwt/dune b/src/client-ocurl-lwt/dune
index 64fb6217..41dd39a9 100644
--- a/src/client-ocurl-lwt/dune
+++ b/src/client-ocurl-lwt/dune
@@ -8,6 +8,7 @@
   opentelemetry
   opentelemetry.atomic
   opentelemetry-client
+  opentelemetry-client.lwt
   pbrt
   mtime
   mtime.clock.os
diff --git a/src/client-ocurl-lwt/opentelemetry_client_ocurl_lwt.ml b/src/client-ocurl-lwt/opentelemetry_client_ocurl_lwt.ml
index 0041e2af..b31160ed 100644
--- a/src/client-ocurl-lwt/opentelemetry_client_ocurl_lwt.ml
+++ b/src/client-ocurl-lwt/opentelemetry_client_ocurl_lwt.ml
@@ -3,9 +3,8 @@
    https://github.com/open-telemetry/oteps/blob/main/text/0099-otlp-http.md
  *)
 
-module OT = Opentelemetry
+module Config = Config
 open Opentelemetry
-open Opentelemetry_util
 open Opentelemetry_client
 open Common_
 
@@ -17,40 +16,14 @@ external reraise : exn -> 'a = "%reraise"
 (** This is equivalent to [Lwt.reraise]. We inline it here so we don't force to
     use Lwt's latest version *)
 
-type error =
-  [ `Status of int * Opentelemetry.Proto.Status.status
-  | `Failure of string
-  | `Sysbreak
-  ]
+type error = Export_error.t
 
+(* TODO: emit this in a metric in [tick()] if self tracing is enabled? *)
 let n_errors = Atomic.make 0
 
-let n_dropped = Atomic.make 0
-
-let report_err_ = function
-  | `Sysbreak -> Printf.eprintf "opentelemetry: ctrl-c captured, stopping\n%!"
-  | `Failure msg ->
-    Format.eprintf "@[<2>opentelemetry: export failed: %s@]@." msg
-  | `Status
-      ( code,
-        {
-          Opentelemetry.Proto.Status.code = scode;
-          message;
-          details;
-          _presence = _;
-        } ) ->
-    let pp_details out l =
-      List.iter
-        (fun s -> Format.fprintf out "%S;@ " (Bytes.unsafe_to_string s))
-        l
-    in
-    Format.eprintf
-      "@[<2>opentelemetry: export failed with@ http code=%d@ status \
-       {@[code=%ld;@ message=%S;@ details=[@[%a@]]@]}@]@."
-      code scode
-      (Bytes.unsafe_to_string message)
-      pp_details details
+let report_err_ = Export_error.report_err
 
+(** HTTP client *)
 module Httpc : sig
   type t
 
@@ -68,24 +41,22 @@ end = struct
   open Opentelemetry.Proto
   open Lwt.Syntax
 
-  type t = unit
+  type t = Curl.t
 
-  let create () : t = ()
+  let create () : t = Ezcurl_core.make ()
 
-  let cleanup _self = ()
-
-  (* FIXME: absolutely need some rate limiting somewhere, ideally as early
-     as possible so we can measure how many resources we drop *)
+  let cleanup self = Ezcurl_core.delete self
 
   (* send the content to the remote endpoint/path *)
-  let send (_self : t) ~url ~decode (bod : string) : ('a, error) result Lwt.t =
+  let send (self : t) ~url ~decode (bod : string) : ('a, error) result Lwt.t =
     let* r =
       let headers =
         ("Content-Type", "application/x-protobuf")
         :: ("Accept", "application/x-protobuf")
         :: Config.Env.get_headers ()
       in
-      Ezcurl_lwt.post ~headers ~params:[] ~url ~content:(`String bod) ()
+      Ezcurl_lwt.post ~client:self ~headers ~params:[] ~url
+        ~content:(`String bod) ()
     in
     match r with
     | Error (code, msg) ->
@@ -115,53 +86,36 @@ end = struct
         in
         Lwt.return r)
     | Ok { code; body; _ } ->
-      let dec = Pbrt.Decoder.of_string body in
-
-      let r =
-        try
-          let status = Status.decode_pb_status dec in
-          Error (`Status (code, status))
-        with e ->
-          let bt = Printexc.get_backtrace () in
-          Error
-            (`Failure
-               (spf
-                  "httpc: decoding of status (url=%S, code=%d) failed with:\n\
-                   %s\n\
-                   status: %S\n\
-                   %s"
-                  url code (Printexc.to_string e) body bt))
-      in
-      Lwt.return r
+      let err = Export_error.decode_invalid_http_response ~url ~code body in
+      Lwt.return (Error err)
 end
 
-module Exporter_impl = struct
+module Consumer_impl = struct
+  module CNotifier = Opentelemetry_client_lwt.Notifier
   open Lwt.Syntax
 
-  let[@inline] push_to_batch b e =
-    if e <> [] then (
-      match Batch.push b e with
-      | `Ok -> ()
-      | `Dropped -> Atomic.incr n_dropped
-    )
-
   type state = {
     stop: bool Atomic.t;
     cleaned: bool Atomic.t;  (** True when we cleaned up after closing *)
     config: Config.t;
-    encoder_pool: Pbrt.Encoder.t Rpool.t;
-    traces: Proto.Trace.span Batch.t;
-    logs: Proto.Logs.log_record Batch.t;
-    metrics: Proto.Metrics.metric Batch.t;
+    q: Any_resource.t Bounded_queue.t;
+    notify: CNotifier.t;
   }
 
-  let send_http_ (st : state) (httpc : Httpc.t) ~url data : unit Lwt.t =
+  let shutdown self =
+    if not (Atomic.exchange self.stop true) then (
+      CNotifier.trigger self.notify;
+      CNotifier.delete self.notify
+    )
+
+  let send_http_ (self : state) (httpc : Httpc.t) ~url (data : string) :
+      unit Lwt.t =
     let* r = Httpc.send httpc ~url ~decode:(`Ret ()) data in
     match r with
     | Ok () -> Lwt.return ()
     | Error `Sysbreak ->
       Printf.eprintf "ctrl-c captured, stopping\n%!";
-      Atomic.set st.stop true;
+      Atomic.set self.stop true;
       Lwt.return ()
     | Error err ->
       (* TODO: log error _via_ otel? *)
@@ -170,179 +124,113 @@ module Exporter_impl = struct
       (* avoid crazy error loop *)
       Lwt_unix.sleep 3.
 
-  let send_metrics_http (st : state) client
+  let send_metrics_http (st : state) client ~encoder
       (l : Proto.Metrics.resource_metrics list) =
-    let msg =
-      let@ encoder = Rpool.with_resource st.encoder_pool in
-      Signal.Encode.metrics ~encoder l
-    in
+    let msg = Signal.Encode.metrics ~encoder l in
+    Pbrt.Encoder.reset encoder;
     send_http_ st client msg ~url:st.config.url_metrics
 
-  let send_traces_http st client (l : Proto.Trace.resource_spans list) =
-    let msg =
-      let@ encoder = Rpool.with_resource st.encoder_pool in
-      Signal.Encode.traces ~encoder l
-    in
+  let send_traces_http st client ~encoder (l : Proto.Trace.resource_spans list)
+      =
+    let msg = Signal.Encode.traces ~encoder l in
+    Pbrt.Encoder.reset encoder;
     send_http_ st client msg ~url:st.config.url_traces
 
-  let send_logs_http st client (l : Proto.Logs.resource_logs list) =
-    let msg =
-      let@ encoder = Rpool.with_resource st.encoder_pool in
-      Signal.Encode.logs ~encoder l
-    in
+  let send_logs_http st client ~encoder (l : Proto.Logs.resource_logs list) =
+    let msg = Signal.Encode.logs ~encoder l in
+    Pbrt.Encoder.reset encoder;
     send_http_ st client msg ~url:st.config.url_logs
 
-  (* emit metrics, if the batch is full or timeout lapsed *)
-  let emit_metrics_maybe (st : state) ~now ?force httpc : bool Lwt.t =
-    match Batch.pop_if_ready ?force ~now st.metrics with
-    | None -> Lwt.return false
-    | Some l ->
-      let res = Util_resources.make_resource_metrics l in
-      let+ () = send_metrics_http st httpc [ res ] in
-      true
+  let tick (self : state) = CNotifier.trigger self.notify
 
-  let emit_traces_maybe st ~now ?force httpc : bool Lwt.t =
-    match Batch.pop_if_ready ?force ~now st.traces with
-    | None -> Lwt.return false
-    | Some l ->
-      let res = Util_resources.make_resource_spans l in
-      let+ () = send_traces_http st httpc [ res ] in
-      true
+  let start_worker (self : state) : unit =
+    let client = Httpc.create () in
+    let encoder = Pbrt.Encoder.create () in
 
-  let emit_logs_maybe st ~now ?force httpc : bool Lwt.t =
-    match Batch.pop_if_ready ?force ~now st.logs with
-    | None -> Lwt.return false
-    | Some l ->
-      let res = Util_resources.make_resource_logs l in
-      let+ () = send_logs_http st httpc [ res ] in
-      true
-
-  let emit_all_force st (httpc : Httpc.t) : unit Lwt.t =
-    let now = Mtime_clock.now () in
-    let+ (_ : bool) = emit_traces_maybe st ~now ~force:true httpc
-    and+ (_ : bool) = emit_logs_maybe st ~now ~force:true httpc
-    and+ (_ : bool) = emit_metrics_maybe st ~now ~force:true httpc in
-    ()
-
-  let[@inline] guard_exn_ where f =
-    try f ()
-    with e ->
-      let bt = Printexc.get_backtrace () in
-      Printf.eprintf
-        "opentelemetry-ocurl-lwt: uncaught exception in %s: %s\n%s\n%!" where
-        (Printexc.to_string e) bt
-
-  (* Lwt task that calls [tick()] regularly, to help enforce timeouts *)
-  let setup_ticker_ st ~tick ~finally () =
-    let rec tick_loop () =
-      if Atomic.get st.stop then (
-        finally ();
+    (* loop on [q] *)
+    let rec loop () : unit Lwt.t =
+      if Atomic.get self.stop then
         Lwt.return ()
-      ) else
-        let* () = Lwt_unix.sleep 0.5 in
-        let* () = tick () in
-        tick_loop ()
-    in
-    Lwt.async tick_loop
-
-  (* make an emitter.
-
-   exceptions inside should be caught, see
-   https://opentelemetry.io/docs/reference/specification/error-handling/ *)
-  let create ~stop ~(config : Config.t) () : OT.Exporter.t =
-    let open Proto in
-    let encoder_pool =
-      Rpool.create
-        ~mk_item:(fun () -> Pbrt.Encoder.create ~size:1024 ())
-        ~max_size:32 ~clear:Pbrt.Encoder.reset ()
-    in
-
-    (* local helpers *)
-    let timeout =
-      if config.batch_timeout_ms > 0 then
-        Some Mtime.Span.(config.batch_timeout_ms * ms)
       else
-        None
+        let* () =
+          match Bounded_queue.try_pop self.q with
+          | `Closed ->
+            shutdown self;
+            Lwt.return ()
+          | `Empty -> CNotifier.wait self.notify
+          | `Item (R_logs logs) -> send_logs_http self client ~encoder logs
+          | `Item (R_metrics ms) -> send_metrics_http self client ~encoder ms
+          | `Item (R_spans spans) -> send_traces_http self client ~encoder spans
+        in
+        loop ()
     in
 
-    let st =
+    Lwt.async (fun () ->
+        Lwt.finalize loop (fun () ->
+            Httpc.cleanup client;
+            Lwt.return ()))
+
+  let default_n_workers = 50
+
+  let create_state ~stop ~config ~q () : state =
+    let self =
       {
         stop;
         config;
+        q;
         cleaned = Atomic.make false;
-        encoder_pool;
-        traces = Batch.make ?batch:config.batch_traces ?timeout ();
-        metrics = Batch.make ?batch:config.batch_metrics ?timeout ();
-        logs = Batch.make ?batch:config.batch_logs ?timeout ();
+        notify = CNotifier.create ();
       }
     in
-    let httpc = Httpc.create () in
-    let ticker = Cb_set.create () in
 
-    let tick_ () =
-      if Config.Env.get_debug () then
-        Printf.eprintf "tick (from %d)\n%!" (Thread.id @@ Thread.self ());
-      Cb_set.trigger ticker;
-      let now = Mtime_clock.now () in
-      let+ (_ : bool) = emit_traces_maybe st ~now httpc
-      and+ (_ : bool) = emit_logs_maybe st ~now httpc
-      and+ (_ : bool) = emit_metrics_maybe st ~now httpc in
-      ()
+    (* start workers *)
+    let n_workers =
+      min 2
+        (max 500
+           (Option.value ~default:default_n_workers
+              config.http_concurrency_level))
     in
+    for _i = 1 to n_workers do
+      start_worker self
+    done;
 
-    setup_ticker_ st ~tick:tick_ ~finally:ignore ();
+    self
 
-    (* we make sure that this is thread-safe, even though we don't have a
-       background thread. There can still be a ticker thread, and there
-       can also be several user threads that produce spans and call
-       the emit functions. *)
-    object
-      method send_trace e =
-        let@ () = guard_exn_ "push trace" in
-        push_to_batch st.traces e;
-        let now = Mtime_clock.now () in
-        Lwt.async (fun () ->
-            let+ (_ : bool) = emit_traces_maybe st ~now httpc in
-            ())
+  let to_consumer (self : state) : Any_resource.t Consumer.t =
+    let active () = not (Atomic.get self.stop) in
+    let shutdown ~on_done =
+      shutdown self;
+      on_done ()
+    in
+    let tick () = tick self in
+    { active; tick; shutdown }
 
-      method send_metrics e =
-        let@ () = guard_exn_ "push metrics" in
-        push_to_batch st.metrics e;
-        let now = Mtime_clock.now () in
-        Lwt.async (fun () ->
-            let+ (_ : bool) = emit_metrics_maybe st ~now httpc in
-            ())
-
-      method send_logs e =
-        let@ () = guard_exn_ "push logs" in
-        push_to_batch st.logs e;
-        let now = Mtime_clock.now () in
-        Lwt.async (fun () ->
-            let+ (_ : bool) = emit_logs_maybe st ~now httpc in
-            ())
-
-      method add_on_tick_callback f = Cb_set.register ticker f
-
-      (* if called in a blocking context: work in the background *)
-      method tick () = Lwt.async tick_
-
-      method cleanup ~on_done () =
-        if Config.Env.get_debug () then
-          Printf.eprintf "opentelemetry: exiting…\n%!";
-        Lwt.async (fun () ->
-            let* () = emit_all_force st httpc in
-            Httpc.cleanup httpc;
-            on_done ();
-            Lwt.return ())
-    end
+  let consumer ~stop ~config () : Consumer.any_resource_builder =
+    {
+      start_consuming =
+        (fun q ->
+          let st = create_state ~stop ~config ~q () in
+          to_consumer st);
+    }
 end
 
-let create_backend ?(stop = Atomic.make false) ?(config = Config.make ()) () =
-  Exporter_impl.create ~stop ~config ()
+let create_consumer ?(stop = Atomic.make false) ?(config = Config.make ()) () =
+  Consumer_impl.consumer ~stop ~config ()
+
+let create_exporter ?stop ?(config = Config.make ()) () =
+  let consumer = create_consumer ?stop ~config () in
+  let bq =
+    Bounded_queue_sync.create
+      ~high_watermark:Bounded_queue.Defaults.high_watermark ()
+  in
+  Exporter_queued.create ~q:bq ~consumer ()
+  |> Exporter_add_batching.add_batching ~config
+
+let create_backend = create_exporter
 
 let setup_ ?stop ?config () : unit =
   let exp = create_backend ?stop ?config () in
-  OT.Exporter.Main_exporter.set exp;
+  Main_exporter.set exp;
   ()
 
 let setup ?stop ?config ?(enable = true) () =
@@ -350,9 +238,7 @@ let setup ?stop ?config ?(enable = true) () =
 
 let remove_backend () : unit Lwt.t =
   let done_fut, done_u = Lwt.wait () in
-  OT.Exporter.Main_exporter.remove
-    ~on_done:(fun () -> Lwt.wakeup_later done_u ())
-    ();
+  Main_exporter.remove ~on_done:(fun () -> Lwt.wakeup_later done_u ()) ();
   done_fut
 
 let with_setup ?stop ?(config = Config.make ()) ?(enable = true) () f : _ Lwt.t
diff --git a/src/client-ocurl-lwt/opentelemetry_client_ocurl_lwt.mli b/src/client-ocurl-lwt/opentelemetry_client_ocurl_lwt.mli
index 0e02d495..713ea70a 100644
--- a/src/client-ocurl-lwt/opentelemetry_client_ocurl_lwt.mli
+++ b/src/client-ocurl-lwt/opentelemetry_client_ocurl_lwt.mli
@@ -12,10 +12,21 @@ val set_headers : (string * string) list -> unit
 
 module Config = Config
 
-val create_backend :
+val create_consumer :
+  ?stop:bool Atomic.t ->
+  ?config:Config.t ->
+  unit ->
+  Opentelemetry_client.Consumer.any_resource_builder
+(** Consumer that pulls from a queue *)
+
+val create_exporter :
   ?stop:bool Atomic.t -> ?config:Config.t -> unit -> Opentelemetry.Exporter.t
 (** Create a new backend using lwt and ezcurl-lwt *)
 
+val create_backend :
+  ?stop:bool Atomic.t -> ?config:Config.t -> unit -> Opentelemetry.Exporter.t
+[@@deprecated "use create_exporter"]
+
 val setup :
   ?stop:bool Atomic.t -> ?config:Config.t -> ?enable:bool -> unit -> unit
 (** Setup endpoint. This modifies {!Opentelemetry.Collector.backend}.