diff --git a/pkgs/development/ocaml-modules/bencode/default.nix b/pkgs/development/ocaml-modules/bencode/default.nix
new file mode 100644
index 000000000000..310d7f24d006
--- /dev/null
+++ b/pkgs/development/ocaml-modules/bencode/default.nix
@@ -0,0 +1,34 @@
+{
+  lib,
+  buildDunePackage,
+  fetchFromGitHub,
+  ounit,
+  qcheck,
+}:
+
+buildDunePackage rec {
+  pname = "bencode";
+  version = "2.0";
+  minimalOCamlVersion = "4.02.0";
+
+  src = fetchFromGitHub {
+    owner = "rgrinberg";
+    repo = "bencode";
+    tag = version;
+    hash = "sha256-sEMS9oBOPeFX1x7cHjbQhCD2QI5yqC+550pPqqMsVws=";
+  };
+
+  doCheck = true;
+  checkInputs = [
+    ounit
+    qcheck
+  ];
+
+  meta = {
+    description = "Bencode (.torrent file format) reader/writer in OCaml ";
+    homepage = "https://github.com/rgrinberg/bencode";
+    changelog = "https://github.com/rgrinberg/bencode/blob/${version}/Changelog.md";
+    license = lib.licenses.mit;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/cbor/default.nix b/pkgs/development/ocaml-modules/cbor/default.nix
new file mode 100644
index 000000000000..09287676de68
--- /dev/null
+++ b/pkgs/development/ocaml-modules/cbor/default.nix
@@ -0,0 +1,35 @@
+{
+  lib,
+  buildDunePackage,
+  fetchurl,
+  ocplib-endian,
+  yojson,
+}:
+
+buildDunePackage rec {
+  pname = "cbor";
+  version = "0.5";
+
+  minimalOCamlVersion = "4.07.0";
+
+  src = fetchurl {
+    url = "https://github.com/ygrek/ocaml-cbor/releases/download/${version}/ocaml-cbor-${version}.tar.gz";
+    hash = "sha256-4mpm/fv9X5uFRQO8XqBhOpxYwZreEtJ3exIwN6YulKM=";
+  };
+
+  propagatedBuildInputs = [
+    ocplib-endian
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    yojson
+  ];
+
+  meta = {
+    description = "CBOR encoder/decoder (RFC 7049) - native OCaml implementation";
+    homepage = "https://github.com/ygrek/ocaml-cbor";
+    license = lib.licenses.mit;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders-bencode/default.nix b/pkgs/development/ocaml-modules/decoders-bencode/default.nix
new file mode 100644
index 000000000000..6e2198ff2b6d
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders-bencode/default.nix
@@ -0,0 +1,36 @@
+{
+  lib,
+  buildDunePackage,
+  decoders,
+  bencode,
+  containers,
+  ounit2,
+}:
+
+buildDunePackage rec {
+  pname = "decoders-bencode";
+
+  # sub-package built separately from the same source
+  inherit (decoders) src version;
+
+  minimalOCamlVersion = "4.03.0";
+
+  propagatedBuildInputs = [
+    decoders
+    bencode
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    containers
+    ounit2
+  ];
+
+  meta = {
+    description = "Bencode backend for decoders";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders-cbor/default.nix b/pkgs/development/ocaml-modules/decoders-cbor/default.nix
new file mode 100644
index 000000000000..067beb013cb2
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders-cbor/default.nix
@@ -0,0 +1,36 @@
+{
+  lib,
+  buildDunePackage,
+  decoders,
+  cbor,
+  containers,
+  ounit2,
+}:
+
+buildDunePackage rec {
+  pname = "decoders-cbor";
+
+  # sub-package built separately from the same source
+  inherit (decoders) src version;
+
+  minimalOCamlVersion = "4.03.0";
+
+  propagatedBuildInputs = [
+    decoders
+    cbor
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    containers
+    ounit2
+  ];
+
+  meta = {
+    description = "CBOR backend for decoders";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders-ezjsonm/default.nix b/pkgs/development/ocaml-modules/decoders-ezjsonm/default.nix
new file mode 100644
index 000000000000..acb5c16cffa7
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders-ezjsonm/default.nix
@@ -0,0 +1,36 @@
+{
+  lib,
+  buildDunePackage,
+  decoders,
+  ezjsonm,
+  containers,
+  ounit2,
+}:
+
+buildDunePackage rec {
+  pname = "decoders-ezjsonm";
+
+  # sub-package built separately from the same source
+  inherit (decoders) src version;
+
+  minimalOCamlVersion = "4.03.0";
+
+  propagatedBuildInputs = [
+    decoders
+    ezjsonm
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    containers
+    ounit2
+  ];
+
+  meta = {
+    description = "Ezjsonm backend for decoders";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders-ezxmlm/default.nix b/pkgs/development/ocaml-modules/decoders-ezxmlm/default.nix
new file mode 100644
index 000000000000..685265dddff1
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders-ezxmlm/default.nix
@@ -0,0 +1,34 @@
+{
+  lib,
+  buildDunePackage,
+  decoders,
+  ezxmlm,
+  containers,
+}:
+
+buildDunePackage rec {
+  pname = "decoders-ezxmlm";
+
+  # sub-package built separately from the same source
+  inherit (decoders) src version;
+
+  minimalOCamlVersion = "4.03.0";
+
+  propagatedBuildInputs = [
+    decoders
+    ezxmlm
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    containers
+  ];
+
+  meta = {
+    description = "Ezxmlm backend for decoders";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders-jsonaf/default.nix b/pkgs/development/ocaml-modules/decoders-jsonaf/default.nix
new file mode 100644
index 000000000000..d6e01a3273c5
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders-jsonaf/default.nix
@@ -0,0 +1,36 @@
+{
+  lib,
+  buildDunePackage,
+  decoders,
+  jsonaf ? null,
+  containers,
+  ounit2,
+}:
+
+buildDunePackage rec {
+  pname = "decoders-jsonaf";
+
+  # sub-package built separately from the same source
+  inherit (decoders) src version;
+
+  minimalOCamlVersion = "4.11.0";
+
+  propagatedBuildInputs = [
+    decoders
+    jsonaf
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    containers
+    ounit2
+  ];
+
+  meta = {
+    description = "Jsonaf backend for decoders";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders-jsonm/default.nix b/pkgs/development/ocaml-modules/decoders-jsonm/default.nix
new file mode 100644
index 000000000000..c354ae20d076
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders-jsonm/default.nix
@@ -0,0 +1,36 @@
+{
+  lib,
+  buildDunePackage,
+  decoders,
+  jsonm,
+  containers,
+  ounit2,
+}:
+
+buildDunePackage rec {
+  pname = "decoders-jsonm";
+
+  # sub-package built separately from the same source
+  inherit (decoders) src version;
+
+  minimalOCamlVersion = "4.03.0";
+
+  propagatedBuildInputs = [
+    decoders
+    jsonm
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    containers
+    ounit2
+  ];
+
+  meta = {
+    description = "Jsonm backend for decoders";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders-msgpck/default.nix b/pkgs/development/ocaml-modules/decoders-msgpck/default.nix
new file mode 100644
index 000000000000..6004a2503aac
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders-msgpck/default.nix
@@ -0,0 +1,36 @@
+{
+  lib,
+  buildDunePackage,
+  decoders,
+  msgpck,
+  containers,
+  ounit2,
+}:
+
+buildDunePackage rec {
+  pname = "decoders-msgpck";
+
+  # sub-package built separately from the same source
+  inherit (decoders) src version;
+
+  minimalOCamlVersion = "4.03.0";
+
+  propagatedBuildInputs = [
+    decoders
+    msgpck
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    containers
+    ounit2
+  ];
+
+  meta = {
+    description = "Msgpck backend for decoders";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders-sexplib/default.nix b/pkgs/development/ocaml-modules/decoders-sexplib/default.nix
new file mode 100644
index 000000000000..5b12b422fded
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders-sexplib/default.nix
@@ -0,0 +1,38 @@
+{
+  lib,
+  buildDunePackage,
+  decoders,
+  sexplib,
+  sexplib0,
+  containers,
+  ounit2,
+}:
+
+buildDunePackage rec {
+  pname = "decoders-sexplib";
+
+  # sub-package built separately from the same source
+  inherit (decoders) src version;
+
+  minimalOCamlVersion = "4.03.0";
+
+  propagatedBuildInputs = [
+    decoders
+    sexplib
+    sexplib0
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    containers
+    ounit2
+  ];
+
+  meta = {
+    description = "sexplib backend for decoders";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders-yojson/default.nix b/pkgs/development/ocaml-modules/decoders-yojson/default.nix
new file mode 100644
index 000000000000..8da0e05a69ff
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders-yojson/default.nix
@@ -0,0 +1,36 @@
+{
+  lib,
+  buildDunePackage,
+  decoders,
+  yojson,
+  containers,
+  ounit2,
+}:
+
+buildDunePackage rec {
+  pname = "decoders-yojson";
+
+  # sub-package built separately from the same source
+  inherit (decoders) src version;
+
+  minimalOCamlVersion = "4.03.0";
+
+  propagatedBuildInputs = [
+    decoders
+    yojson
+  ];
+
+  doCheck = true;
+  checkInputs = [
+    containers
+    ounit2
+  ];
+
+  meta = {
+    description = "Yojson backend for decoders";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/development/ocaml-modules/decoders/default.nix b/pkgs/development/ocaml-modules/decoders/default.nix
new file mode 100644
index 000000000000..42e68503ac8d
--- /dev/null
+++ b/pkgs/development/ocaml-modules/decoders/default.nix
@@ -0,0 +1,31 @@
+{
+  lib,
+  buildDunePackage,
+  fetchurl,
+  containers,
+}:
+
+buildDunePackage rec {
+  pname = "decoders";
+  version = "1.0.0";
+
+  minimalOCamlVersion = "4.03.0";
+
+  src = fetchurl {
+    url = "https://github.com/mattjbray/ocaml-decoders/releases/download/v${version}/${pname}-${version}.tbz";
+    hash = "sha256-R/55xBAtD3EO/zzq7zExANnfPHlFg00884o5dCpXNZc=";
+  };
+
+  doCheck = true;
+  checkInputs = [
+    containers
+  ];
+
+  meta = {
+    description = "Elm-inspired decoders for Ocaml";
+    homepage = "https://github.com/mattjbray/ocaml-decoders";
+    changelog = "https://github.com/mattjbray/ocaml-decoders/blob/${version}/CHANGES.md";
+    license = lib.licenses.isc;
+    maintainers = with lib.maintainers; [ infinidoge ];
+  };
+}
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 087745078bc6..00bc16314969 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -88,6 +88,8 @@ let
 
         benchmark = callPackage ../development/ocaml-modules/benchmark { };
 
+        bencode = callPackage ../development/ocaml-modules/bencode { };
+
         bheap = callPackage ../development/ocaml-modules/bheap { };
 
         bigarray-compat = callPackage ../development/ocaml-modules/bigarray-compat { };
@@ -202,6 +204,8 @@ let
           git-binary = pkgs.git;
         };
 
+        cbor = callPackage ../development/ocaml-modules/cbor { };
+
         cfstream = callPackage ../development/ocaml-modules/cfstream { };
 
         chacha = callPackage ../development/ocaml-modules/chacha { };
@@ -326,6 +330,26 @@ let
 
         dbf = callPackage ../development/ocaml-modules/dbf { };
 
+        decoders = callPackage ../development/ocaml-modules/decoders { };
+
+        decoders-bencode = callPackage ../development/ocaml-modules/decoders-bencode { };
+
+        decoders-cbor = callPackage ../development/ocaml-modules/decoders-cbor { };
+
+        decoders-ezjsonm = callPackage ../development/ocaml-modules/decoders-ezjsonm { };
+
+        decoders-ezxmlm = callPackage ../development/ocaml-modules/decoders-ezxmlm { };
+
+        decoders-jsonaf = callPackage ../development/ocaml-modules/decoders-jsonaf { };
+
+        decoders-jsonm = callPackage ../development/ocaml-modules/decoders-jsonm { };
+
+        decoders-msgpck = callPackage ../development/ocaml-modules/decoders-msgpck { };
+
+        decoders-sexplib = callPackage ../development/ocaml-modules/decoders-sexplib { };
+
+        decoders-yojson = callPackage ../development/ocaml-modules/decoders-yojson { };
+
         decompress = callPackage ../development/ocaml-modules/decompress { };
 
         dedukti = callPackage ../development/ocaml-modules/dedukti { };