diff --git a/packages/eio/eio.0.1/opam b/packages/eio/eio.0.1/opam
new file mode 100644
index 000000000000..dd9bc3c29423
--- /dev/null
+++ b/packages/eio/eio.0.1/opam
@@ -0,0 +1,50 @@
+opam-version: "2.0"
+synopsis: "Effect-based direct-style IO API for OCaml"
+description: "An effect-based IO API for multicore OCaml with fibres."
+maintainer: ["anil@recoil.org"]
+authors: ["Anil Madhavapeddy" "Thomas Leonard"]
+license: "ISC"
+homepage: "https://github.com/ocaml-multicore/eio"
+doc: "https://ocaml-multicore.github.io/eio/"
+bug-reports: "https://github.com/ocaml-multicore/eio/issues"
+depends: [
+  "dune" {>= "2.9"}
+  "ocaml" {>= "4.12.0"}
+  "base-domains"
+  "cstruct" {>= "6.0.1"}
+  "lwt-dllist"
+  "optint" {>= "0.1.0"}
+  "psq" {>= "0.2.0"}
+  "fmt" {>= "0.8.9"}
+  "astring" {>= "0.8.5" & with-test}
+  "crowbar" {>= "0.2" & with-test}
+  "mtime" {>= "1.2.0"}
+  "alcotest" {>= "1.4.0" & with-test}
+  "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/ocaml-multicore/eio.git"
+url {
+  src:
+    "https://github.com/ocaml-multicore/eio/releases/download/v0.1/eio_main-0.1.tbz"
+  checksum: [
+    "sha256=671bedef03a2646d13f6e18b6e18c3509be7688fa19b4c48c9f0656959716878"
+    "sha512=8aa4993576bd716c0a3df70bb7cc55507ab6f810b38bdb8d66d0d5a6b5853eb80d705b106a6d55cfc31d39a18f938ef0f107968a4eb2f40e0a80887c66a8764c"
+  ]
+}
+x-commit-hash: "ba1fbbe60b94500c79556585134ffbe0dd1ec2fa"
diff --git a/packages/eio_linux/eio_linux.0.1/opam b/packages/eio_linux/eio_linux.0.1/opam
new file mode 100644
index 000000000000..e0210d0a49c0
--- /dev/null
+++ b/packages/eio_linux/eio_linux.0.1/opam
@@ -0,0 +1,46 @@
+opam-version: "2.0"
+synopsis: "Eio implementation for Linux using io-uring"
+description: "An eio implementation for Linux using io-uring."
+maintainer: ["anil@recoil.org"]
+authors: ["Anil Madhavapeddy" "Thomas Leonard"]
+license: "ISC"
+homepage: "https://github.com/ocaml-multicore/eio"
+doc: "https://ocaml-multicore.github.io/eio/"
+bug-reports: "https://github.com/ocaml-multicore/eio/issues"
+depends: [
+  "dune" {>= "2.9"}
+  "alcotest" {>= "1.4.0" & with-test}
+  "base-domains"
+  "eio" {= version}
+  "mdx" {>= "1.10.0" & with-test}
+  "logs" {>= "0.7.0"}
+  "fmt" {>= "0.8.9"}
+  "uring" {>= "0.2"}
+  "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/ocaml-multicore/eio.git"
+url {
+  src:
+    "https://github.com/ocaml-multicore/eio/releases/download/v0.1/eio_main-0.1.tbz"
+  checksum: [
+    "sha256=671bedef03a2646d13f6e18b6e18c3509be7688fa19b4c48c9f0656959716878"
+    "sha512=8aa4993576bd716c0a3df70bb7cc55507ab6f810b38bdb8d66d0d5a6b5853eb80d705b106a6d55cfc31d39a18f938ef0f107968a4eb2f40e0a80887c66a8764c"
+  ]
+}
+x-commit-hash: "ba1fbbe60b94500c79556585134ffbe0dd1ec2fa"
diff --git a/packages/eio_luv/eio_luv.0.1/opam b/packages/eio_luv/eio_luv.0.1/opam
new file mode 100644
index 000000000000..cc99ceb2e842
--- /dev/null
+++ b/packages/eio_luv/eio_luv.0.1/opam
@@ -0,0 +1,46 @@
+opam-version: "2.0"
+synopsis: "Eio implementation using luv (libuv)"
+description: "An eio implementation for most platforms, using luv."
+maintainer: ["anil@recoil.org"]
+authors: ["Anil Madhavapeddy" "Thomas Leonard"]
+license: "ISC"
+homepage: "https://github.com/ocaml-multicore/eio"
+doc: "https://ocaml-multicore.github.io/eio/"
+bug-reports: "https://github.com/ocaml-multicore/eio/issues"
+depends: [
+  "dune" {>= "2.9"}
+  "base-domains"
+  "eio" {= version}
+  "luv" {>= "0.5.11"}
+  "luv_unix" {>= "0.5.0"}
+  "mdx" {>= "1.10.0" & with-test}
+  "logs" {>= "0.7.0"}
+  "fmt" {>= "0.8.9"}
+  "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/ocaml-multicore/eio.git"
+url {
+  src:
+    "https://github.com/ocaml-multicore/eio/releases/download/v0.1/eio_main-0.1.tbz"
+  checksum: [
+    "sha256=671bedef03a2646d13f6e18b6e18c3509be7688fa19b4c48c9f0656959716878"
+    "sha512=8aa4993576bd716c0a3df70bb7cc55507ab6f810b38bdb8d66d0d5a6b5853eb80d705b106a6d55cfc31d39a18f938ef0f107968a4eb2f40e0a80887c66a8764c"
+  ]
+}
+x-commit-hash: "ba1fbbe60b94500c79556585134ffbe0dd1ec2fa"
diff --git a/packages/eio_main/eio_main.0.1/opam b/packages/eio_main/eio_main.0.1/opam
new file mode 100644
index 000000000000..a4e66c068ea4
--- /dev/null
+++ b/packages/eio_main/eio_main.0.1/opam
@@ -0,0 +1,40 @@
+opam-version: "2.0"
+synopsis: "Effect-based direct-style IO mainloop for OCaml"
+description: "Selects an appropriate Eio backend for the current platform."
+maintainer: ["anil@recoil.org"]
+authors: ["Anil Madhavapeddy" "Thomas Leonard"]
+license: "ISC"
+homepage: "https://github.com/ocaml-multicore/eio"
+doc: "https://ocaml-multicore.github.io/eio/"
+bug-reports: "https://github.com/ocaml-multicore/eio/issues"
+depends: [
+  "dune" {>= "2.9"}
+  "eio_linux" {= version & os = "linux"}
+  "eio_luv" {= version}
+  "odoc" {with-doc}
+]
+build: [
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "--promote-install-files=false"
+    "@install"
+    "@doc" {with-doc}
+  ]
+  ["dune" "install" "-p" name "--create-install-files" name]
+]
+dev-repo: "git+https://github.com/ocaml-multicore/eio.git"
+url {
+  src:
+    "https://github.com/ocaml-multicore/eio/releases/download/v0.1/eio_main-0.1.tbz"
+  checksum: [
+    "sha256=671bedef03a2646d13f6e18b6e18c3509be7688fa19b4c48c9f0656959716878"
+    "sha512=8aa4993576bd716c0a3df70bb7cc55507ab6f810b38bdb8d66d0d5a6b5853eb80d705b106a6d55cfc31d39a18f938ef0f107968a4eb2f40e0a80887c66a8764c"
+  ]
+}
+x-commit-hash: "ba1fbbe60b94500c79556585134ffbe0dd1ec2fa"