diff --git a/dune-project b/dune-project
index 962f8fc45..60a8869bb 100644
--- a/dune-project
+++ b/dune-project
@@ -18,10 +18,10 @@
   (synopsis "Public internals of the Kappa tool suite")
   (depends
    (ocaml ( >= 4.05.0 ))
-   num
-   re
    (yojson ( >= 2.0 ))
    (lwt ( >= 4.2.0 ))
+   num
+   re
    stdlib-shims
    fmt
    logs
@@ -34,13 +34,13 @@
   (name kappa-binaries)
   (synopsis "Command line interfaces of the Kappa tool suite")
   (depends
-   (ocaml ( >= 4.04.0 ))
-   num
-   re
-   (yojson ( >= 1.6.0 ))
-   (lwt ( >= 4.2.0 ))
-   fmt
-   logs
+   (ocaml ( >= 4.05.0 ))
+   (yojson ( = 2.1.0 ))
+   (lwt ( = 5.7.0 ))
+   (num ( = 1.5))
+   (re ( = 1.11.0))
+   (fmt ( = 0.9.0))
+   (logs ( = 0.7.0))
    kappa-library
    )
   (depopts
@@ -52,33 +52,69 @@
   (synopsis "Backends for an interactive use of the Kappa tool suite")
   (depends
    (ocaml ( >= 4.05.0 ))
-   num
-   re
-   (yojson ( >= 1.6.0 ))
-   (lwt ( >= 4.2.0 ))
-   fmt
-   logs
+   (yojson ( = 2.1.0 ))
+   (lwt ( = 5.7.0 ))
+   (num ( = 1.5))
+   (re ( = 1.11.0))
+   (fmt ( = 0.9.0))
+   (logs ( = 0.7.0))
+   (atdgen-runtime ( = 2.15.0))
+   (atdgen ( = 2.15.0)) ; TODO: find a way to specify as build dependency only, as with the `build` package variable in opam
    kappa-library
-   atdgen-runtime
-   atdgen ; TODO: find a way to specify as build dependency only, as with the `build` package variable in opam
    )
 )
 
 (package
   (name kappa-server)
-  (synopsis "HTTP server to query the Kappa tool suite")
+  (synopsis "Browser app for an interactive use of the Kappa tool suite")
   (depends
    (ocaml ( >= 4.05.0 ))
-   num
-   re
-   (yojson ( >= 1.6.0 ))
-   (lwt ( >= 4.2.0 ))
-   fmt
-   logs
+   (yojson ( = 2.1.0 ))
+   (lwt ( = 5.7.0 ))
+   (js_of_ocaml ( = 5.7.0))
+   (num ( = 1.5))
+   (re ( = 1.11.0))
+   (fmt ( = 0.9.0))
+   (logs ( = 0.7.0))
+   (atdgen-runtime ( = 2.15.0))
+   (atdgen ( = 2.15.0)) ; TODO: find a way to specify as build dependency only, as with the `build` package variable in opam
+   (lwt_react ( = 1.2.0))
+   (tyxml-ppx ( = 4.6.0))
+   (js_of_ocaml-ppx ( = 5.7.0))
+   (js_of_ocaml-lwt ( = 5.7.0))
+   (js_of_ocaml-tyxml ( = 5.7.0))
    kappa-binaries
    kappa-agents
    cohttp-lwt-unix
    atdgen-runtime
    atdgen ; TODO: find a way to specify as build dependency only, as with the `build` package variable in opam
    )
+  ; does not build executables as there seem to be no way to build js exes in a package
+)
+
+(package
+  (name kappa-webapp)
+  (synopsis "Browser app for an interactive use of the Kappa tool suite")
+  (depends
+   (ocaml ( >= 4.05.0 ))
+   (yojson ( = 2.1.0 ))
+   (lwt ( = 5.7.0 ))
+   (js_of_ocaml ( = 5.7.0))
+   (num ( = 1.5))
+   (re ( = 1.11.0))
+   (fmt ( = 0.9.0))
+   (logs ( = 0.7.0))
+   (atdgen-runtime ( = 2.15.0))
+   (atdgen ( = 2.15.0)) ; TODO: find a way to specify as build dependency only, as with the `build` package variable in opam
+   (lwt_react ( = 1.2.0))
+   (tyxml-ppx ( = 4.6.0))
+   (js_of_ocaml-ppx ( = 5.7.0))
+   (js_of_ocaml-lwt ( = 5.7.0))
+   (js_of_ocaml-tyxml ( = 5.7.0))
+   (atdgen-runtime ( = 2.15.0))
+   (atdgen ( = 2.15.0)) ; TODO: find a way to specify as build dependency only, as with the `build` package variable in opam
+   kappa-binaries
+   kappa-agents
+   )
+  ; does not build executables as there seem to be no way to build js exes in a package
 )
diff --git a/kappa-agents.opam b/kappa-agents.opam
index a330a684b..2d29b0028 100644
--- a/kappa-agents.opam
+++ b/kappa-agents.opam
@@ -23,15 +23,15 @@ bug-reports: "https://github.com/Kappa-Dev/KappaTools/issues"
 depends: [
   "dune" {>= "2.9"}
   "ocaml" {>= "4.05.0"}
-  "num"
-  "re"
-  "yojson" {>= "1.6.0"}
-  "lwt" {>= "4.2.0"}
-  "fmt"
-  "logs"
+  "yojson" {= "2.1.0"}
+  "lwt" {= "5.7.0"}
+  "num" {= "1.5"}
+  "re" {= "1.11.0"}
+  "fmt" {= "0.9.0"}
+  "logs" {= "0.7.0"}
+  "atdgen-runtime" {= "2.15.0"}
+  "atdgen" {= "2.15.0"}
   "kappa-library"
-  "atdgen-runtime"
-  "atdgen"
   "odoc" {with-doc}
 ]
 build: [
diff --git a/kappa-binaries.opam b/kappa-binaries.opam
index eadd1b190..f7be78c92 100644
--- a/kappa-binaries.opam
+++ b/kappa-binaries.opam
@@ -22,13 +22,13 @@ doc:
 bug-reports: "https://github.com/Kappa-Dev/KappaTools/issues"
 depends: [
   "dune" {>= "2.9"}
-  "ocaml" {>= "4.04.0"}
-  "num"
-  "re"
-  "yojson" {>= "1.6.0"}
-  "lwt" {>= "4.2.0"}
-  "fmt"
-  "logs"
+  "ocaml" {>= "4.05.0"}
+  "yojson" {= "2.1.0"}
+  "lwt" {= "5.7.0"}
+  "num" {= "1.5"}
+  "re" {= "1.11.0"}
+  "fmt" {= "0.9.0"}
+  "logs" {= "0.7.0"}
   "kappa-library"
   "odoc" {with-doc}
 ]
diff --git a/kappa-library.opam b/kappa-library.opam
index 8455d819a..0df3970d6 100644
--- a/kappa-library.opam
+++ b/kappa-library.opam
@@ -23,10 +23,10 @@ bug-reports: "https://github.com/Kappa-Dev/KappaTools/issues"
 depends: [
   "dune" {>= "2.9"}
   "ocaml" {>= "4.05.0"}
-  "num"
-  "re"
   "yojson" {>= "2.0"}
   "lwt" {>= "4.2.0"}
+  "num"
+  "re"
   "stdlib-shims"
   "fmt"
   "logs"
diff --git a/kappa-webapp.opam b/kappa-webapp.opam
new file mode 100644
index 000000000..e6c0f1627
--- /dev/null
+++ b/kappa-webapp.opam
@@ -0,0 +1,62 @@
+# This file is generated by dune, edit dune-project instead
+opam-version: "2.0"
+version: "4.1~dev"
+synopsis: "Browser app for an interactive use of the Kappa tool suite"
+maintainer: [
+  "Antoine Pouille <antoine.a.pouille@inria.fr>"
+  "Pierre Boutillier <pierre.boutillier@laposte.net>"
+]
+authors: [
+  "Jean Krivine"
+  "Jérôme Feret"
+  "Pierre Boutillier"
+  "Ioana Cristescu"
+  "Mutaamba Maasha"
+  "Lý Kim Quyên"
+  "Antoine Pouille"
+]
+license: "LGPL-3.0-only"
+homepage: "https://kappalanguage.org/"
+doc:
+  "https://kappalanguage.org/sites/kappalanguage.org/files/inline-files/Kappa_Manual.pdf"
+bug-reports: "https://github.com/Kappa-Dev/KappaTools/issues"
+depends: [
+  "dune" {>= "2.9"}
+  "ocaml" {>= "4.05.0"}
+  "yojson" {= "2.1.0"}
+  "lwt" {= "5.7.0"}
+  "js_of_ocaml" {= "5.7.0"}
+  "num" {= "1.5"}
+  "re" {= "1.11.0"}
+  "fmt" {= "0.9.0"}
+  "logs" {= "0.7.0"}
+  "atdgen-runtime" {= "2.15.0"}
+  "atdgen" {= "2.15.0"}
+  "lwt_react" {= "1.2.0"}
+  "tyxml-ppx" {= "4.6.0"}
+  "js_of_ocaml-ppx" {= "5.7.0"}
+  "js_of_ocaml-lwt" {= "5.7.0"}
+  "js_of_ocaml-tyxml" {= "5.7.0"}
+  "atdgen-runtime" {= "2.15.0"}
+  "atdgen" {= "2.15.0"}
+  "kappa-binaries"
+  "kappa-agents"
+  "odoc" {with-doc}
+]
+build: [
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "--promote-install-files=false"
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
+  ["dune" "install" "-p" name "--create-install-files" name]
+]
+dev-repo: "git+https://github.com/Kappa-Dev/KappaTools.git"