diff --git a/emci/rattler_build.py b/emci/rattler_build.py
index a2107fec7..17d6c0275 100644
--- a/emci/rattler_build.py
+++ b/emci/rattler_build.py
@@ -26,9 +26,9 @@ def build_with_rattler(recipe=None, recipes_dir=None, emscripten_wasm32=False):
     
     # add conda forge and emscripten-forge channels
     cmd.extend([
-        "-c", "microsoft",
+        "-c", "https://repo.mamba.pm/emscripten-forge",
         "-c", "conda-forge",
-        "-c", "https://repo.mamba.pm/emscripten-forge"
+        "-c", "microsoft",
     ])
 
     # pass existing env vars to subprocess
diff --git a/recipes/recipes/pytester/rattler_recipe.yaml b/recipes/recipes/pytester/rattler_recipe.yaml
index b8f92d943..393a568a8 100644
--- a/recipes/recipes/pytester/rattler_recipe.yaml
+++ b/recipes/recipes/pytester/rattler_recipe.yaml
@@ -13,7 +13,8 @@ outputs:
       version: ${{ version }}
 
     build:
-      number: 4
+      number: 6
+
       noarch: python
 
     requirements:
@@ -33,7 +34,7 @@ outputs:
       name: pytester-run
       version: ${{ version }}
     build:
-      number: 4
+      number: 6
       noarch: generic
     requirements:
       run:
diff --git a/recipes/recipes/rust/LICENSE b/recipes/recipes/rust/LICENSE
new file mode 100644
index 000000000..468cd79a8
--- /dev/null
+++ b/recipes/recipes/rust/LICENSE
@@ -0,0 +1,23 @@
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/recipes/recipes/rust/activate-rust.sh b/recipes/recipes/rust/activate-rust.sh
new file mode 100644
index 000000000..1913c4e4c
--- /dev/null
+++ b/recipes/recipes/rust/activate-rust.sh
@@ -0,0 +1,47 @@
+#!/bin/bash
+
+echo "Activating Rust"
+
+
+
+export RUSTUP_HOME=$BUILD_PREFIX/.rustup
+export CARGO_HOME=$BUILD_PREFIX/.cargo
+export PATH=$CARGO_HOME/bin:$PATH
+
+
+#echo $PKG_VERSION > ${PREFIX}/.rust_version
+
+# is there a .bashenv file?
+if [ -f ${PREFIX}/.bashenv ]; then
+    # create a backup of the .bashenv file
+    cp ${PREFIX}/.bashenv ${PREFIX}/.bashenv.bak
+fi
+
+
+# load the rust version from the .rust_version file
+
+curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y #--default-toolchain=1.78.0
+rustup install nightly-2024-04-22
+rustup default nightly-2024-04-22
+rustup target add wasm32-unknown-emscripten
+
+
+
+
+export OPENSSL_INCLUDE_PATH=$PREFIX/include
+export OPENSSL_LIBRARY_PATH=$PREFIX/lib
+export OPENSSL_DIR=$PREFIX/lib
+export WASM32_UNKNOWN_EMSCRIPTEN_OPENSSL_LIB_DIR=$PREFIX/lib
+export WASM32_UNKNOWN_EMSCRIPTEN_OPENSSL_DIR=$PREFIX/lib
+export WASM32_UNKNOWN_EMSCRIPTEN_OPENSSL_INCLUDE_DIR=$PREFIX/include
+
+
+export PYO3_CROSS=1
+export PYO3_PYTHON=python3
+export PYO3_CROSS_PYTHON_VERSION=$PY_VER
+export PYO3_CROSS_LIB_DIR=$PREFIX/lib
+export PYO3_CROSS_INCLUDE_DIR=$PREFIX/include
+export PYO3_PYTHON=python
+
+export CARGO_BUILD_TARGET="wasm32-unknown-emscripten"
+export LDFLAGS="$LDFLAGS -L${PREFIX}/lib"
\ No newline at end of file
diff --git a/recipes/recipes/rust/build.sh b/recipes/recipes/rust/build.sh
new file mode 100644
index 000000000..63c87e25a
--- /dev/null
+++ b/recipes/recipes/rust/build.sh
@@ -0,0 +1,7 @@
+mkdir -p ${PREFIX}/etc/conda/activate.d
+mkdir -p ${PREFIX}/etc/conda/deactivate.d
+
+
+cp "${RECIPE_DIR}"/activate-rust.sh   ${PREFIX}/etc/conda/activate.d/activate_z-${PKG_NAME}.sh
+cp "${RECIPE_DIR}"/deactivate-rust.sh ${PREFIX}/etc/conda/deactivate.d/deactivate_z-${PKG_NAME}.sh
+
diff --git a/recipes/recipes/rust/deactivate-rust.sh b/recipes/recipes/rust/deactivate-rust.sh
new file mode 100644
index 000000000..3ffe1cb21
--- /dev/null
+++ b/recipes/recipes/rust/deactivate-rust.sh
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+echo "Deactivating Rust"
+
+unset CARGO_HOME
+unset RUSTUP_HOME
+
+
+
+# is there a .bashenv.bak file?
+if [ -f ${PREFIX}/.bashenv.bak ]; then
+    # restore the .bashenv file
+    mv ${PREFIX}/.bashenv.bak ${PREFIX}/.bashenv
+fi
\ No newline at end of file
diff --git a/recipes/recipes/rust/rattler_recipe.yaml b/recipes/recipes/rust/rattler_recipe.yaml
new file mode 100644
index 000000000..2c57041aa
--- /dev/null
+++ b/recipes/recipes/rust/rattler_recipe.yaml
@@ -0,0 +1,22 @@
+context:
+  name: rust
+  version: "1.79.0"
+
+package:
+  name: ${{ name|lower }}
+  version: ${{ version }}
+
+
+build:
+  number: 29
+
+requirements:
+  build:
+    - curl
+
+about:
+  summary: rust
+
+extra:
+  recipe-maintainers:
+    - DerThorsten
diff --git a/recipes/recipes_emscripten/cryptography/build.sh b/recipes/recipes_emscripten/cryptography/build.sh
index 6f8b4b7c5..7c4dcd955 100644
--- a/recipes/recipes_emscripten/cryptography/build.sh
+++ b/recipes/recipes_emscripten/cryptography/build.sh
@@ -1,3 +1,3 @@
 #!/bin/bash
-export LDFLAGS="$LDFLAGS -L${PREFIX}/lib"
-${PYTHON} -m pip  install .
+${PYTHON} -m pip  install . -vvv
+
diff --git a/recipes/recipes_emscripten/cryptography/patches/0001-Tell-rust-lang-libc-that-time_t-is-64-bits.patch b/recipes/recipes_emscripten/cryptography/patches/0001-Tell-rust-lang-libc-that-time_t-is-64-bits.patch
new file mode 100644
index 000000000..1ee33c0c8
--- /dev/null
+++ b/recipes/recipes_emscripten/cryptography/patches/0001-Tell-rust-lang-libc-that-time_t-is-64-bits.patch
@@ -0,0 +1,27 @@
+From aeadf0c7223c0b8c7e209f6b555dfc91de31a34c Mon Sep 17 00:00:00 2001
+From: Hood Chatham <roberthoodchatham@gmail.com>
+Date: Mon, 29 Jan 2024 16:34:05 -0800
+Subject: [PATCH] Tell rust-lang/libc that time_t is 64 bits
+
+See upstream PR:
+https://github.com/rust-lang/libc/pull/3569#event-11634944887
+---
+ src/rust/Cargo.toml | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/src/rust/Cargo.toml b/src/rust/Cargo.toml
+index 2322486d0..52e7231d7 100644
+--- a/src/rust/Cargo.toml
++++ b/src/rust/Cargo.toml
+@@ -7,6 +7,9 @@ publish = false
+ # This specifies the MSRV
+ rust-version = "1.63.0"
+ 
++[patch.crates-io]
++libc = { git = 'https://github.com/hoodmane/libc.git', branch = 'emscripten-time_t-64-bit-2' }
++
+ [dependencies]
+ once_cell = "1"
+ cfg-if = "1"
+-- 
+2.25.1
\ No newline at end of file
diff --git a/recipes/recipes_emscripten/cryptography/rattler_recipe.yaml b/recipes/recipes_emscripten/cryptography/rattler_recipe.yaml
new file mode 100644
index 000000000..8c343d032
--- /dev/null
+++ b/recipes/recipes_emscripten/cryptography/rattler_recipe.yaml
@@ -0,0 +1,47 @@
+context:
+  name: cryptography
+  version: '42.0.2'
+
+package:
+  name: cryptography
+  version: ${{ version }}
+
+source:
+- url: https://files.pythonhosted.org/packages/0f/6f/40f1b5c6bafc809dd21a9e577458ecc1d8062a7e10148d140f402b535eaa/cryptography-${{version}}.tar.gz
+  sha256: e0ec52ba3c7f1b7d813cd52649a5b3ef1fc0d433219dc8c93827c57eab6cf888
+  patches:
+    - patches/0001-Tell-rust-lang-libc-that-time_t-is-64-bits.patch
+
+build:
+  number: 2
+
+requirements:
+  build:
+    - cross-python_${{target_platform}}
+    - cffi == 1.15.1
+    - openssl
+    - setuptools-rust 
+    - rust
+    
+  host:
+    - python
+    - openssl
+    - cffi == 1.15.1 
+  run:
+    - cffi == 1.15.1
+tests:
+  - script: pytester
+    requirements:
+      build:
+        - pytester
+      run:
+        - pytester-run
+    files:
+      recipe:
+        - test_import_cryptography.py
+
+extra:
+  emscripten_tests:
+    python:
+      pytest_files:
+      - test_import_cryptography.py
diff --git a/recipes/recipes_emscripten/cryptography/recipe.yaml b/recipes/recipes_emscripten/cryptography/recipe.yaml
deleted file mode 100644
index 0f43d3777..000000000
--- a/recipes/recipes_emscripten/cryptography/recipe.yaml
+++ /dev/null
@@ -1,35 +0,0 @@
-context:
-  name: cryptography
-  version: '3.3.2'
-
-package:
-  name: cryptography
-  version: '{{ version }}'
-
-source:
-- url: https://pypi.io/packages/source/{{ name[0] }}/{{ name }}/{{ name }}-{{ version }}.tar.gz
-  sha256: 5a60d3780149e13b7a6ff7ad6526b38846354d11a15e21068e57073e29e19bed
-
-build:
-  number: 1
-  ignore_run_exports:
-    - python_abi
-
-requirements:
-  build:
-    - cross-python_emscripten-wasm32
-    - cffi == 1.15.1
-    - openssl
-    - pip
-  host:
-    - python
-    - openssl
-    - cffi == 1.15.1
-  #run:
-  #  #- cffi
-
-extra:
-  emscripten_tests:
-    python:
-      pytest_files:
-      - test_import_cryptography.py
diff --git a/recipes/recipes_emscripten/cryptography/test_import_cryptography.py b/recipes/recipes_emscripten/cryptography/test_import_cryptography.py
index 19ed17736..6fd86a9e3 100644
--- a/recipes/recipes_emscripten/cryptography/test_import_cryptography.py
+++ b/recipes/recipes_emscripten/cryptography/test_import_cryptography.py
@@ -2,7 +2,10 @@
 def test_import_cryptography():
     import cryptography
     import cryptography.fernet
+    from cryptography.hazmat.primitives.padding import ANSIX923, PKCS7
     import cryptography.hazmat
     import cryptography.utils
     import cryptography.x509
-    
\ No newline at end of file
+    
+
+
diff --git a/recipes/recipes_emscripten/pycrdt/build.sh b/recipes/recipes_emscripten/pycrdt/build.sh
new file mode 100644
index 000000000..47c63b944
--- /dev/null
+++ b/recipes/recipes_emscripten/pycrdt/build.sh
@@ -0,0 +1,6 @@
+#!/bin/bash
+
+
+export MATURIN_PYTHON_SYSCONFIGDATA_DIR=${PREFIX}/etc/conda/_sysconfigdata__emscripten_wasm32-emscripten.py
+${PYTHON} -m pip  install . -vvv
+
diff --git a/recipes/recipes_emscripten/pycrdt/rattler_recipe.yaml b/recipes/recipes_emscripten/pycrdt/rattler_recipe.yaml
new file mode 100644
index 000000000..86b0bf992
--- /dev/null
+++ b/recipes/recipes_emscripten/pycrdt/rattler_recipe.yaml
@@ -0,0 +1,41 @@
+context:
+  name: pycrdt
+  version: '0.8.19'
+
+package:
+  name: ${{name}}
+  version: ${{ version }}
+
+source:
+- url: https://github.com/jupyter-server/pycrdt/archive/refs/tags/v${{version}}.tar.gz
+  sha256: 7284bd052c1b7ee56d1f3ffbc7dcd0c72181c6cd92ae3744c63ee80373827b48
+
+build:
+  number: 0
+
+requirements:
+  build:
+    - cross-python_${{target_platform}}
+    - cffi == 1.15.1
+    - setuptools-rust 
+    - rust
+    - maturin
+    
+  host:
+    - python
+    - openssl
+    - cffi == 1.15.1
+  run:
+    - cffi == 1.15.1
+    - typing_extensions
+    
+tests:
+  - script: pytester
+    requirements:
+      build:
+        - pytester
+      run:
+        - pytester-run
+    files:
+      recipe:
+        - test_pycrdt.py
\ No newline at end of file
diff --git a/recipes/recipes_emscripten/pycrdt/test_pycrdt.py b/recipes/recipes_emscripten/pycrdt/test_pycrdt.py
new file mode 100644
index 000000000..82ccd62b3
--- /dev/null
+++ b/recipes/recipes_emscripten/pycrdt/test_pycrdt.py
@@ -0,0 +1,38 @@
+import json
+from pycrdt import Array, Doc, Map, Text 
+
+def callback(events, event):
+    events.append(
+        dict(
+            delta=event.delta,
+            path=event.path,
+        )
+    )
+
+
+def test_str():
+    doc = Doc()
+    map2 = Map({"key": "val"})
+    array1 = Array([2, 3, map2])
+    map1 = Map({"foo": array1})
+    array0 = Array([0, 1, None, map1])
+    doc["array"] = array0
+    assert str(array0) == '[0.0,1.0,null,{"foo":[2.0,3.0,{"key":"val"}]}]'
+
+
+def test_nested():
+    doc = Doc()
+    text1 = Text("my_text1")
+    array1 = Array([0, "foo", 2])
+    text2 = Text("my_text2")
+    map1 = Map({"foo": [3, 4, 5], "bar": "hello", "baz": text2})
+    array0 = Array([text1, array1, map1])
+    doc["array"] = array0
+    ref = [
+        "my_text1",
+        [0, "foo", 2],
+        {"bar": "hello", "foo": [3, 4, 5], "baz": "my_text2"},
+    ]
+    assert json.loads(str(array0)) == ref
+    assert isinstance(array0[2], Map)
+    assert isinstance(array0[2]["baz"], Text)
\ No newline at end of file
diff --git a/recipes/recipes_emscripten/pydantic_core/build.sh b/recipes/recipes_emscripten/pydantic_core/build.sh
new file mode 100644
index 000000000..47c63b944
--- /dev/null
+++ b/recipes/recipes_emscripten/pydantic_core/build.sh
@@ -0,0 +1,6 @@
+#!/bin/bash
+
+
+export MATURIN_PYTHON_SYSCONFIGDATA_DIR=${PREFIX}/etc/conda/_sysconfigdata__emscripten_wasm32-emscripten.py
+${PYTHON} -m pip  install . -vvv
+
diff --git a/recipes/recipes_emscripten/pydantic_core/rattler_recipe.yaml b/recipes/recipes_emscripten/pydantic_core/rattler_recipe.yaml
new file mode 100644
index 000000000..e4df7cfe0
--- /dev/null
+++ b/recipes/recipes_emscripten/pydantic_core/rattler_recipe.yaml
@@ -0,0 +1,44 @@
+context:
+  name: pydantic_core
+  version: '2.16.2'
+
+package:
+  name: pydantic_core
+  version: ${{ version }}
+
+source:
+- url: https://files.pythonhosted.org/packages/0d/72/64550ef171432f97d046118a9869ad774925c2f442589d5f6164b8288e85/pydantic_core-${{ version }}.tar.gz
+  sha256: 0ba503850d8b8dcc18391f10de896ae51d37fe5fe43dbfb6a35c5c5cad271a06
+
+build:
+  number: 2
+
+requirements:
+  build:
+    - cross-python_${{target_platform}}
+    - cffi == 1.15.1
+    - openssl
+    - setuptools-rust 
+    - rust
+    - maturin
+    - typing_extensions
+    
+  host:
+    - python
+    - openssl
+    - cffi == 1.15.1
+    - typing_extensions
+  run:
+    - cffi == 1.15.1
+    - typing_extensions
+    
+tests:
+  - script: pytester
+    requirements:
+      build:
+        - pytester
+      run:
+        - pytester-run
+    files:
+      recipe:
+        - test_pydantic_core.py
\ No newline at end of file
diff --git a/recipes/recipes_emscripten/pydantic_core/test_pydantic_core.py b/recipes/recipes_emscripten/pydantic_core/test_pydantic_core.py
new file mode 100644
index 000000000..8c22880ff
--- /dev/null
+++ b/recipes/recipes_emscripten/pydantic_core/test_pydantic_core.py
@@ -0,0 +1,40 @@
+
+def test_pydantic_core():
+    from pydantic_core import SchemaValidator, ValidationError
+
+
+    v = SchemaValidator(
+        {
+            'type': 'typed-dict',
+            'fields': {
+                'name': {
+                    'type': 'typed-dict-field',
+                    'schema': {
+                        'type': 'str',
+                    },
+                },
+                'age': {
+                    'type': 'typed-dict-field',
+                    'schema': {
+                        'type': 'int',
+                        'ge': 18,
+                    },
+                },
+                'is_developer': {
+                    'type': 'typed-dict-field',
+                    'schema': {
+                        'type': 'default',
+                        'schema': {'type': 'bool'},
+                        'default': True,
+                    },
+                },
+            },
+        }
+    )
+
+    r1 = v.validate_python({'name': 'Samuel', 'age': 35})
+    assert r1 == {'name': 'Samuel', 'age': 35, 'is_developer': True}
+
+    # pydantic-core can also validate JSON directly
+    r2 = v.validate_json('{"name": "Samuel", "age": 35}')
+    assert r1 == r2
\ No newline at end of file