diff --git a/manifest/main.ml b/manifest/main.ml
index 78cac9b5e3e7b07169e2ee833681b3fafe371a12..60de38c4b2005159a4eb441fc800700f2198b592 100644
--- a/manifest/main.ml
+++ b/manifest/main.ml
@@ -2210,6 +2210,7 @@ let tezos_proxy_rpc =
         tezos_mockup_proxy;
         tezos_rpc;
         tezos_proxy;
+        lwt_unix;
       ]
 
 let _tezos_proxy_tests =
@@ -3173,6 +3174,7 @@ let _tezos_proxy_server =
          tezos_stdlib_unix |> open_;
          cmdliner;
          lwt_exit;
+         lwt_unix;
          tezos_proxy;
          tezos_proxy_server_config;
          tezos_rpc_http_client_unix;
diff --git a/src/bin_proxy_server/dune b/src/bin_proxy_server/dune
index 3718b93e0d9ca7fe6c1eb7fe127441cc3fecd4c3..54cd6d74f9fe7346418e57a47a3f11b7d199926f 100644
--- a/src/bin_proxy_server/dune
+++ b/src/bin_proxy_server/dune
@@ -14,6 +14,7 @@
   tezos-stdlib-unix
   cmdliner
   lwt-exit
+  lwt.unix
   tezos-proxy
   tezos-proxy-server-config
   tezos-rpc-http-client-unix
diff --git a/src/bin_proxy_server/main_proxy_server.ml b/src/bin_proxy_server/main_proxy_server.ml
index cc472be301f3c9f81cc2cbf20c868b1011d93619..69f6fd72ca4946bb6929cc0738ae448d307b3de4 100644
--- a/src/bin_proxy_server/main_proxy_server.ml
+++ b/src/bin_proxy_server/main_proxy_server.ml
@@ -153,6 +153,7 @@ let main_promise (config_file : string option)
   in
   let dir =
     Tezos_proxy.Proxy_services.build_directory
+      ~sleep:Lwt_unix.sleep
       printer
       http_ctxt
       (Tezos_proxy.Proxy_services.Proxy_server sym_block_caching_time)
diff --git a/src/bin_proxy_server/tezos-proxy-server.opam b/src/bin_proxy_server/tezos-proxy-server.opam
index f3b895f7ad0babe14a3effde474d46307ffd0f98..eb5b5ba6ec209db7af23887153ae990a459c90fa 100644
--- a/src/bin_proxy_server/tezos-proxy-server.opam
+++ b/src/bin_proxy_server/tezos-proxy-server.opam
@@ -13,6 +13,7 @@ depends: [
   "tezos-stdlib-unix"
   "cmdliner"
   "lwt-exit"
+  "lwt" { >= "5.4.0" }
   "tezos-proxy"
   "tezos-proxy-server-config"
   "tezos-rpc-http-client-unix"
diff --git a/src/lib_proxy/proxy_services.ml b/src/lib_proxy/proxy_services.ml
index 82c43a994954ad0b67b1c407dace3d01c5864cb4..5e9779d65332b08b27bcea1179766fe1c8c7e8ac 100644
--- a/src/lib_proxy/proxy_services.ml
+++ b/src/lib_proxy/proxy_services.ml
@@ -162,7 +162,8 @@ module Env_cache =
 
 module Env_cache_lwt = Ringo_lwt.Functors.Make_result (Env_cache)
 
-let schedule_clearing (printer : Tezos_client_base.Client_context.printer)
+let schedule_clearing ~(sleep : float -> unit Lwt.t)
+    (printer : Tezos_client_base.Client_context.printer)
     (rpc_context : RPC_context.generic)
     (proxy_env : Registration.proxy_environment) (mode : mode) envs_cache key
     chain block =
@@ -209,7 +210,7 @@ let schedule_clearing (printer : Tezos_client_base.Client_context.printer)
             | Ok (Some x) -> Lwt.return (Int64.to_float x))
       in
       let schedule () : _ Lwt.t =
-        let* () = Lwt_unix.sleep time_between_blocks in
+        let* () = sleep time_between_blocks in
         Env_cache_lwt.remove envs_cache key ;
         Events.(emit clearing_data (chain_string, block_string))
       in
@@ -249,7 +250,8 @@ let protocols protocol_hash =
             next_protocol = protocol_hash;
           }))
 
-let build_directory (printer : Tezos_client_base.Client_context.printer)
+let build_directory ~(sleep : float -> unit Lwt.t)
+    (printer : Tezos_client_base.Client_context.printer)
     (rpc_context : RPC_context.generic) (mode : mode)
     (proxy_env : Registration.proxy_environment) : unit RPC_directory.t =
   let (module Proxy_environment) = proxy_env in
@@ -314,6 +316,7 @@ let build_directory (printer : Tezos_client_base.Client_context.printer)
       fill_b2h @@ initial_context.block_hash ;
       let*! () =
         schedule_clearing
+          ~sleep
           printer
           rpc_context
           proxy_env
diff --git a/src/lib_proxy/proxy_services.mli b/src/lib_proxy/proxy_services.mli
index e2b6bcb4512a4588efcb164f7680540ba738e359..dda2d0c9527bcae980df31b6cdfa755b47305080 100644
--- a/src/lib_proxy/proxy_services.mli
+++ b/src/lib_proxy/proxy_services.mli
@@ -52,6 +52,7 @@ type mode =
       or [tezos-proxy-server] is running.
     - [env] is a protocol-specific module used to create the context passed when executing a RPC. *)
 val build_directory :
+  sleep:(float -> unit Lwt.t) ->
   Tezos_client_base.Client_context.printer ->
   RPC_context.generic ->
   mode ->
diff --git a/src/lib_proxy/rpc/RPC_client.ml b/src/lib_proxy/rpc/RPC_client.ml
index 901f452db9ec74bb65dbdcc81b49e0c15961c95d..b5f6058b29ba8f2efd39311e0b503de7b91ff455 100644
--- a/src/lib_proxy/rpc/RPC_client.ml
+++ b/src/lib_proxy/rpc/RPC_client.ml
@@ -56,7 +56,12 @@ class http_local_ctxt (printer : Tezos_client_base.Client_context.printer)
   (proxy_env : Registration.proxy_environment) : RPC_context.generic =
   let local_ctxt =
     Tezos_mockup_proxy.RPC_client.local_ctxt
-      (Proxy_services.build_directory printer http_ctxt mode proxy_env)
+      (Proxy_services.build_directory
+         ~sleep:Lwt_unix.sleep
+         printer
+         http_ctxt
+         mode
+         proxy_env)
   in
   let dispatch_local_or_distant ~debug_name ~local ~distant meth path =
     let open Lwt_syntax in
diff --git a/src/lib_proxy/rpc/dune b/src/lib_proxy/rpc/dune
index ce0b9f1a0a11d5737a5c3c314cdf2c93bd62cca8..ebfb277ba01978df0830992c44604ed62b400c48 100644
--- a/src/lib_proxy/rpc/dune
+++ b/src/lib_proxy/rpc/dune
@@ -10,5 +10,6 @@
   tezos-client-base
   tezos-mockup-proxy
   tezos-rpc
-  tezos-proxy)
+  tezos-proxy
+  lwt.unix)
  (flags (:standard -open Tezos_base.TzPervasives)))
diff --git a/src/lib_proxy/tezos-proxy.opam b/src/lib_proxy/tezos-proxy.opam
index 5e9695f7d30133049ea41621bbb69863f7a04d61..9693a68cfbdd460b102e4ff39b16769fb5bac608 100644
--- a/src/lib_proxy/tezos-proxy.opam
+++ b/src/lib_proxy/tezos-proxy.opam
@@ -18,6 +18,7 @@ depends: [
   "tezos-shell-services"
   "tezos-context"
   "tezos-mockup-proxy"
+  "lwt" { >= "5.4.0" }
   "tezos-stdlib-unix" {with-test}
   "tezos-base-test-helpers" {with-test}
   "tezos-test-helpers" {with-test}