diff --git a/lib/client.ml b/lib/client.ml
index 75d6197..dec66cd 100644
--- a/lib/client.ml
+++ b/lib/client.ml
@@ -33,9 +33,20 @@ open Import
 module Logs = (val Logging.setup ~src:"piaf.client" ~doc:"Piaf Client module")
 module Connection_info = Connection.Info
 
+type 'a env = 'a constraint 'a =
+  < clock : _ Eio.Time.clock
+  ; net : [> [ `Generic | `Unix ] Eio.Net.ty ] Eio.Net.t
+  ; ..
+  > as 'a
+
+type required_env =
+  < clock : float Eio.Time.clock_ty Eio.Std.r
+  ; net : Eio_unix.Net.t
+  > env
+
 type t =
   { mutable conn : Connection.t
-  ; env : Eio_unix.Stdenv.base
+  ; env : required_env
   ; sw : Switch.t
   }
 
@@ -437,7 +448,7 @@ let rec send_request_and_handle_response
 let create ?(config = Config.default) ~sw env uri =
   let*! conn_info = Connection_info.of_uri env ~config uri in
   match open_connection ~config ~sw ~uri:conn_info.uri env conn_info with
-  | Ok conn -> Ok { conn; env; sw }
+  | Ok conn -> Ok { conn; env :> required_env; sw }
   | Error (#Error.client as err) -> Error err
 
 let call t ~meth ?(headers = []) ?(body = Body.empty) target =
diff --git a/lib/connection.ml b/lib/connection.ml
index ae7b8ac..db27c02 100644
--- a/lib/connection.ml
+++ b/lib/connection.ml
@@ -35,9 +35,10 @@ module Version = Httpun.Version
 module Logs =
   (val Logging.setup ~src:"piaf.connection" ~doc:"Piaf Connection module")
 
+let order_v4v6 = Eio.Net.Ipaddr.fold ~v4:(fun _ -> -1) ~v6:(fun _ -> 1)
+
 let resolve_host =
-  let order_v4v6 = Eio.Net.Ipaddr.fold ~v4:(fun _ -> -1) ~v6:(fun _ -> 1) in
-  fun (env : Eio_unix.Stdenv.base) ~config ~port hostname ->
+  fun env ~config ~port hostname ->
     let clock = Eio.Stdenv.clock env in
     let network = Eio.Stdenv.net env in
     match
diff --git a/lib/piaf.mli b/lib/piaf.mli
index dd5acdc..578a764 100644
--- a/lib/piaf.mli
+++ b/lib/piaf.mli
@@ -614,12 +614,18 @@ end
       once the request is done. Useful for isolated requests. *)
 
 module Client : sig
+  type 'a env = 'a constraint 'a =
+    < clock : _ Eio.Time.clock
+    ; net : [> [ `Generic | `Unix ] Eio.Net.ty ] Eio.Net.t
+    ; ..
+    > as 'a
+
   type t
 
   val create :
      ?config:Config.t
     -> sw:Eio.Switch.t
-    -> Eio_unix.Stdenv.base
+    -> _ env
     -> Uri.t
     -> (t, [> Error.client ]) result
   (** [create ?config uri] opens a connection to [uri] (initially) that can be
@@ -694,7 +700,7 @@ module Client : sig
        ?config:Config.t
       -> ?headers:(string * string) list
       -> sw:Eio.Switch.t
-      -> Eio_unix.Stdenv.base
+      -> _ env
       -> Uri.t
       -> (Response.t, [> Error.t ]) result
 
@@ -702,7 +708,7 @@ module Client : sig
        ?config:Config.t
       -> ?headers:(string * string) list
       -> sw:Eio.Switch.t
-      -> Eio_unix.Stdenv.base
+      -> _ env
       -> Uri.t
       -> (Response.t, [> Error.t ]) result
 
@@ -711,7 +717,7 @@ module Client : sig
       -> ?headers:(string * string) list
       -> ?body:Body.t
       -> sw:Eio.Switch.t
-      -> Eio_unix.Stdenv.base
+      -> _ env
       -> Uri.t
       -> (Response.t, [> Error.t ]) result
 
@@ -720,7 +726,7 @@ module Client : sig
       -> ?headers:(string * string) list
       -> ?body:Body.t
       -> sw:Eio.Switch.t
-      -> Eio_unix.Stdenv.base
+      -> _ env
       -> Uri.t
       -> (Response.t, [> Error.t ]) result
 
@@ -729,7 +735,7 @@ module Client : sig
       -> ?headers:(string * string) list
       -> ?body:Body.t
       -> sw:Eio.Switch.t
-      -> Eio_unix.Stdenv.base
+      -> _ env
       -> Uri.t
       -> (Response.t, [> Error.t ]) result
 
@@ -738,7 +744,7 @@ module Client : sig
       -> ?headers:(string * string) list
       -> ?body:Body.t
       -> sw:Eio.Switch.t
-      -> Eio_unix.Stdenv.base
+      -> _ env
       -> Uri.t
       -> (Response.t, [> Error.t ]) result
 
@@ -747,7 +753,7 @@ module Client : sig
       -> ?headers:(string * string) list
       -> ?body:Body.t
       -> sw:Eio.Switch.t
-      -> Eio_unix.Stdenv.base
+      -> _ env
       -> meth:Method.t
       -> Uri.t
       -> (Response.t, [> Error.t ]) result
@@ -765,6 +771,13 @@ module Request_info : sig
 end
 
 module Server : sig
+  type 'a env = 'a constraint 'a =
+    < clock : _ Eio.Time.clock
+    ; domain_mgr : _ Eio.Domain_manager.t
+    ; net : [> [ `Generic | `Unix ] Eio.Net.ty ] Eio.Net.t
+    ; ..
+    > as 'a
+
   module Config : sig
     module HTTPS : sig
       type t =
@@ -905,7 +918,7 @@ module Server : sig
     type server := t
     type t
 
-    val start : sw:Eio.Switch.t -> Eio_unix.Stdenv.base -> server -> t
+    val start : sw:Eio.Switch.t -> _ env -> server -> t
     val shutdown : t -> unit
 
     val listen :
@@ -916,7 +929,7 @@ module Server : sig
       -> reuse_port:bool
       -> domains:int
       -> shutdown_timeout:float
-      -> Eio_unix.Stdenv.base
+      -> _ env
       -> connection_handler
       -> t
     (** [listen ~sw ?bind_to_address ~network ~port connection_handler] starts a
diff --git a/lib/server.ml b/lib/server.ml
index 8409185..ea50f95 100644
--- a/lib/server.ml
+++ b/lib/server.ml
@@ -36,6 +36,13 @@ module Reqd = Httpun.Reqd
 module Server_connection = Httpun.Server_connection
 module Config = Server_config
 
+type 'a env = 'a constraint 'a =
+  < clock : _ Eio.Time.clock
+  ; domain_mgr : _ Eio.Domain_manager.t
+  ; net : [> [ `Generic | `Unix ] Eio.Net.ty ] Eio.Net.t
+  ; ..
+  > as 'a
+
 type 'ctx ctx = 'ctx Handler.ctx =
   { ctx : 'ctx
   ; request : Request.t
@@ -181,6 +188,8 @@ module Command = struct
     let empty = Fun.id, Hashtbl.create 0
   end
 
+  type clock = float Eio.Time.clock_ty Eio.Time.clock
+
   type nonrec t =
     { (* types like [_ array] mean per domain * listening address *)
       sockets :
@@ -191,7 +200,7 @@ module Command = struct
           , Eio_unix.Net.stream_socket_ty Eio_unix.Net.stream_socket )
           Hashtbl.t
           array
-    ; clock : float Eio.Time.clock_ty r
+    ; clock : clock
     ; shutdown_timeout : float
     }
 
@@ -322,7 +331,7 @@ module Command = struct
       { sockets = [ listening_socket ]
       ; shutdown_resolvers = Array.map fst resolvers
       ; client_sockets = Array.map snd resolvers
-      ; clock = Eio.Stdenv.clock env
+      ; clock = (Eio.Stdenv.clock env :> clock)
       ; shutdown_timeout
       }
 
@@ -368,7 +377,7 @@ module Command = struct
             https_command.shutdown_resolvers
       ; client_sockets =
           Array.append command.client_sockets https_command.client_sockets
-      ; clock
+      ; clock = (clock :> clock)
       ; shutdown_timeout = config.shutdown_timeout
       }
 end