diff --git a/pkgs/development/ocaml-modules/cohttp/async.nix b/pkgs/development/ocaml-modules/cohttp/async.nix
new file mode 100644
index 00000000000..246397b6081
--- /dev/null
+++ b/pkgs/development/ocaml-modules/cohttp/async.nix
@@ -0,0 +1,22 @@
+{ stdenv, buildDunePackage, async, cohttp, conduit-async, uri, ppx_sexp_conv
+, logs, magic-mime }:
+
+if !stdenv.lib.versionAtLeast cohttp.version "0.99" then
+	cohttp
+else if !stdenv.lib.versionAtLeast async.version "0.13" then
+	throw "cohttp-async needs async-0.13 (hence OCaml >= 4.08)"
+else
+
+	buildDunePackage {
+		pname = "cohttp-async";
+		useDune2 = true;
+		inherit (cohttp) version src;
+
+		buildInputs = [ ppx_sexp_conv ];
+
+		propagatedBuildInputs = [ async cohttp conduit-async logs magic-mime uri ];
+
+		meta = cohttp.meta // {
+			description = "CoHTTP implementation for the Async concurrency library";
+		};
+	}
diff --git a/pkgs/development/ocaml-modules/conduit/async.nix b/pkgs/development/ocaml-modules/conduit/async.nix
new file mode 100644
index 00000000000..f16819ed8ae
--- /dev/null
+++ b/pkgs/development/ocaml-modules/conduit/async.nix
@@ -0,0 +1,19 @@
+{ stdenv, buildDunePackage, async, async_ssl, ppx_sexp_conv, conduit }:
+
+if !stdenv.lib.versionAtLeast conduit.version "1.0"
+then conduit
+else
+
+buildDunePackage {
+	pname = "conduit-async";
+	useDune2 = true;
+	inherit (conduit) version src;
+
+	buildInputs = [ ppx_sexp_conv ];
+
+	propagatedBuildInputs = [ async async_ssl conduit ];
+
+	meta = conduit.meta // {
+		description = "A network connection establishment library for Async";
+	};
+}
diff --git a/pkgs/development/ocaml-modules/conduit/default.nix b/pkgs/development/ocaml-modules/conduit/default.nix
index 7fbeefb3926..27b2a329b26 100644
--- a/pkgs/development/ocaml-modules/conduit/default.nix
+++ b/pkgs/development/ocaml-modules/conduit/default.nix
@@ -18,7 +18,7 @@ buildDunePackage rec {
   propagatedBuildInputs = [ astring ipaddr ipaddr-sexp sexplib uri ];
 
   meta = {
-    description = "Network connection library for TCP and SSL";
+    description = "A network connection establishment library";
     license = stdenv.lib.licenses.isc;
     maintainers = with stdenv.lib.maintainers; [ alexfmpe vbgl ];
     homepage = "https://github.com/mirage/ocaml-conduit";
diff --git a/pkgs/development/ocaml-modules/janestreet/0.13.nix b/pkgs/development/ocaml-modules/janestreet/0.13.nix
index d16ceefd04c..b92027a65a0 100644
--- a/pkgs/development/ocaml-modules/janestreet/0.13.nix
+++ b/pkgs/development/ocaml-modules/janestreet/0.13.nix
@@ -1,5 +1,6 @@
 { janePackage
 , ctypes
+, dune-configurator
 , num
 , octavius
 , ppxlib
@@ -417,6 +418,15 @@ rec {
     propagatedBuildInputs = [ async shell ];
   };
 
+  async_ssl = janePackage {
+    pname = "async_ssl";
+    useDune2 = true;
+    hash = "0z5dbiam5k7ipx9ph4r8nqv0a1ldx1ymxw3xjxgrdjda90lmwf2k";
+    meta.description = "Async wrappers for SSL";
+    buildInputs = [ dune-configurator ];
+    propagatedBuildInputs = [ async ctypes openssl ];
+  };
+
   core_bench = janePackage {
     pname = "core_bench";
     hash = "1nk0i3z8rqrljbf4bc7ljp71g0a4361nh85s2ang0lgxri74zacm";
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index a9bea0a60f6..ba02c3bb524 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -137,12 +137,16 @@ let
 
     cohttp = callPackage ../development/ocaml-modules/cohttp { };
 
+    cohttp-async = callPackage ../development/ocaml-modules/cohttp/async.nix { };
+
     cohttp-lwt = callPackage ../development/ocaml-modules/cohttp/lwt.nix { };
 
     cohttp-lwt-unix = callPackage ../development/ocaml-modules/cohttp/lwt-unix.nix { };
 
     conduit = callPackage ../development/ocaml-modules/conduit { };
 
+    conduit-async = callPackage ../development/ocaml-modules/conduit/async.nix { };
+
     conduit-lwt = callPackage ../development/ocaml-modules/conduit/lwt.nix { };
 
     conduit-lwt-unix = callPackage ../development/ocaml-modules/conduit/lwt-unix.nix { };
@@ -991,7 +995,7 @@ let
     janeStreet =
     if lib.versionOlder "4.08" ocaml.version
     then import ../development/ocaml-modules/janestreet/0.13.nix {
-      inherit ctypes janePackage num octavius ppxlib re;
+      inherit ctypes dune-configurator janePackage num octavius ppxlib re;
       inherit (pkgs) openssl;
     }
     else if lib.versionOlder "4.07" ocaml.version