diff --git a/pkgs/development/python-modules/fnllm/default.nix b/pkgs/development/python-modules/fnllm/default.nix
new file mode 100644
index 000000000000..9ef3701119f2
--- /dev/null
+++ b/pkgs/development/python-modules/fnllm/default.nix
@@ -0,0 +1,80 @@
+{
+  lib,
+  aiolimiter,
+  azure-identity,
+  azure-storage-blob,
+  buildPythonPackage,
+  fetchPypi,
+  hatchling,
+  httpx,
+  json-repair,
+  openai,
+  pydantic,
+  pytest-asyncio,
+  pytestCheckHook,
+  pythonOlder,
+  tenacity,
+  tiktoken,
+}:
+
+buildPythonPackage rec {
+  pname = "fnllm";
+  version = "0.0.11";
+  pyproject = true;
+
+  disabled = pythonOlder "3.11";
+
+  src = fetchPypi {
+    inherit pname version;
+    hash = "sha256-EiCP+HyipL6mpmjb3wjXUr+VRJ9ZO9qsegppNM7gVEk=";
+  };
+
+  build-system = [ hatchling ];
+
+  dependencies = [
+    aiolimiter
+    httpx
+    json-repair
+    pydantic
+    tenacity
+  ];
+
+  optional-dependencies = {
+    azure = [
+      azure-identity
+      azure-storage-blob
+    ];
+    openai = [
+      openai
+      tiktoken
+    ];
+  };
+
+  nativeCheckInputs = [
+    pytest-asyncio
+    pytestCheckHook
+  ] ++ lib.flatten (builtins.attrValues optional-dependencies);
+
+  pythonImportsCheck = [ "fnllm" ];
+
+  disabledTests = [
+    # Tests require network access
+    "chat"
+    "embeddings"
+    "rate_limited"
+    "test_default_operations"
+    "test_estimate_request_tokens"
+    "test_replace_value"
+  ];
+
+  disabledTestPaths = [
+    "tests/unit/caching/test_blob.py"
+  ];
+
+  meta = {
+    description = "A function-based LLM protocol and wrapper";
+    homepage = "https://github.com/microsoft/essex-toolkit/tree/main/python/fnllm";
+    license = lib.licenses.mit;
+    maintainers = with lib.maintainers; [ fab ];
+  };
+}
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 19a640eaf5ef..6832568fb000 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -4854,6 +4854,8 @@ self: super: with self; {
 
   glyphtools = callPackage ../development/python-modules/glyphtools { };
 
+  fnllm = callPackage ../development/python-modules/fnllm { };
+
   foobot-async = callPackage ../development/python-modules/foobot-async { };
 
   foolscap = callPackage ../development/python-modules/foolscap { };