diff --git a/src/generators.h b/src/generators.h
index c6a510739..e6ad6f0e1 100644
--- a/src/generators.h
+++ b/src/generators.h
@@ -99,6 +99,14 @@ struct GeneratorParams : std::enable_shared_from_this<GeneratorParams> {
 
   std::shared_ptr<GeneratorParams> external_owner_;  // Set to 'this' when created by the C API to preserve lifetime
 
+  struct Input {
+    std::string name;
+    std::unique_ptr<OrtValue> value;
+  };
+
+  // A list of extra model inputs that will be matched at runtime based on name
+  std::vector<Input> extra_inputs;
+
   void TryGraphCapture(int max_bs);
 
  private:
diff --git a/src/models/model.cpp b/src/models/model.cpp
index 6f0cc294a..35a9b4ad4 100644
--- a/src/models/model.cpp
+++ b/src/models/model.cpp
@@ -35,6 +35,11 @@ static std::wstring CurrentModulePath() {
 namespace Generators {
 
 State::State(const GeneratorParams& params) : params_{params.shared_from_this()} {
+  // Add extra user inputs
+  for (auto& input : params.extra_inputs) {
+    input_names_.push_back(input.name.c_str());
+    inputs_.push_back(input.value.get());
+  }
 }
 
 void State::Run(OrtSession& session, OrtRunOptions& run_options) {
diff --git a/src/models/model.h b/src/models/model.h
index 5b9ec12d9..165e7c345 100644
--- a/src/models/model.h
+++ b/src/models/model.h
@@ -16,6 +16,8 @@ struct Tokenizer;
 
 void ConvertFp16ToFp32(OrtAllocator& allocator, OrtValue& in, std::unique_ptr<OrtValue>& p_out, DeviceType device_type, cudaStream_t stream);
 
+size_t GetOrtTypeSize(ONNXTensorElementDataType type);
+
 struct State {
   State(const GeneratorParams& params);
   virtual ~State() = default;
diff --git a/src/models/static_buffer.cpp b/src/models/static_buffer.cpp
index 9bc5f50ea..eab776e65 100644
--- a/src/models/static_buffer.cpp
+++ b/src/models/static_buffer.cpp
@@ -1,4 +1,5 @@
 #include "../generators.h"
+#include "model.h"
 #include "static_buffer.h"
 
 namespace Generators {
@@ -8,7 +9,7 @@ StaticBuffer::StaticBuffer(Ort::Allocator* allocator, size_t max_beam_batch_size
 
 std::unique_ptr<OrtValue> StaticBuffer::CreateTensorOnStaticBuffer(std::span<const int64_t> shape,
                                                                    ONNXTensorElementDataType type) {
-  size_t new_bytes = GetElementSize(type) * GetNumElements(shape);
+  size_t new_bytes = GetOrtTypeSize(type) * GetNumElements(shape);
   if (buffer_ == nullptr) {
     // Assuming the first dimension is the batch size
     bytes_ = new_bytes * (max_beam_batch_size_ / shape[0]);
@@ -21,22 +22,6 @@ std::unique_ptr<OrtValue> StaticBuffer::CreateTensorOnStaticBuffer(std::span<con
   return OrtValue::CreateTensor(info_, buffer_, new_bytes, shape, type);
 }
 
-// TODO: same as GetOrtTypeSize() in model.cc. Should be moved to a common place
-size_t StaticBuffer::GetElementSize(ONNXTensorElementDataType type) {
-  switch (type) {
-    case ONNX_TENSOR_ELEMENT_DATA_TYPE_FLOAT16:
-      return sizeof(uint16_t);
-    case ONNX_TENSOR_ELEMENT_DATA_TYPE_FLOAT:
-      return sizeof(float);
-    case ONNX_TENSOR_ELEMENT_DATA_TYPE_INT32:
-      return sizeof(int32_t);
-    case ONNX_TENSOR_ELEMENT_DATA_TYPE_INT64:
-      return sizeof(int64_t);
-    default:
-      throw std::runtime_error("Unsupported tensor element data type");
-  }
-}
-
 size_t StaticBuffer::GetNumElements(std::span<const int64_t> shape) {
   size_t num_elements = 1;
   for (auto dim : shape) {
diff --git a/src/models/static_buffer.h b/src/models/static_buffer.h
index ce9e14686..8c133fdae 100644
--- a/src/models/static_buffer.h
+++ b/src/models/static_buffer.h
@@ -18,7 +18,6 @@ struct StaticBuffer {
                                                        ONNXTensorElementDataType type);
 
  private:
-  size_t GetElementSize(ONNXTensorElementDataType type);
   size_t GetNumElements(std::span<const int64_t> shape);
 
   Ort::Allocator* allocator_{nullptr};
diff --git a/src/python/python.cpp b/src/python/python.cpp
index 1d8a4e567..8bd25a9d3 100644
--- a/src/python/python.cpp
+++ b/src/python/python.cpp
@@ -22,6 +22,34 @@ pybind11::array_t<T> ToPython(std::span<T> v) {
   return pybind11::array_t<T>(v.size(), v.data());
 }
 
+ONNXTensorElementDataType ToTensorType(const pybind11::dtype& type) {
+  switch (type.num()) {
+    case pybind11::detail::npy_api::NPY_INT32_:
+      return Ort::TypeToTensorType<int32_t>::type;
+    case pybind11::detail::npy_api::NPY_UINT32_:
+      return Ort::TypeToTensorType<uint32_t>::type;
+    case 23 /*NPY_FLOAT16*/:
+      return Ort::TypeToTensorType<Ort::Float16_t>::type;
+    case pybind11::detail::npy_api::NPY_FLOAT_:
+      return Ort::TypeToTensorType<float>::type;
+    case pybind11::detail::npy_api::NPY_DOUBLE_:
+      return Ort::TypeToTensorType<double>::type;
+    default:
+      throw std::runtime_error("Unsupported numpy type");
+  }
+}
+
+std::unique_ptr<OrtValue> ToTensor(pybind11::array& v) {
+  auto type = ToTensorType(v.dtype());
+
+  std::vector<int64_t> shape(v.ndim());
+  for (pybind11::ssize_t i = 0; i < v.ndim(); i++)
+    shape[i] = v.shape()[i];
+
+  auto p_memory_info = OrtMemoryInfo::CreateCpu(OrtDeviceAllocator, OrtMemTypeCPU);
+  return OrtValue::CreateTensor(*p_memory_info, v.mutable_data(), v.nbytes(), shape, type);
+}
+
 namespace Generators {
 
 // A roaming array is one that can be in CPU or GPU memory, and will copy the memory as needed to be used from anywhere
@@ -85,6 +113,11 @@ struct PyGeneratorParams {
     }
   }
 
+  void AddExtraInput(const std::string& name, pybind11::array& value) {
+    params_->extra_inputs.push_back({name, ToTensor(value)});
+    refs_.emplace_back(value);
+  }
+
   void SetSearchOptions(const pybind11::kwargs& dict) {
     for (auto& entry : dict) {
       auto name = entry.first.cast<std::string>();
@@ -110,6 +143,8 @@ struct PyGeneratorParams {
   pybind11::array_t<int32_t> py_input_ids_;
   pybind11::array_t<float> py_whisper_input_features_;
   pybind11::array_t<int32_t> py_whisper_decoder_input_ids_;
+
+  std::vector<pybind11::object> refs_;  // References to data we want to ensure doesn't get garbage collected
 };
 
 struct PyGenerator {
@@ -198,6 +233,7 @@ PYBIND11_MODULE(onnxruntime_genai, m) {
       .def_readwrite("input_ids", &PyGeneratorParams::py_input_ids_)
       .def_readwrite("whisper_input_features", &PyGeneratorParams::py_whisper_input_features_)
       .def_readwrite("whisper_decoder_input_ids", &PyGeneratorParams::py_whisper_decoder_input_ids_)
+      .def("add_extra_input", &PyGeneratorParams::AddExtraInput)
       .def("set_search_options", &PyGeneratorParams::SetSearchOptions)  // See config.h 'struct Search' for the options
       .def("try_use_cuda_graph_with_max_batch_size", &PyGeneratorParams::TryUseCudaGraphWithMaxBatchSize);