diff --git a/subprojects/callback-manager/include/callback_manager.hpp b/subprojects/callback-manager/include/callback_manager.hpp
new file mode 100644
index 0000000..e4776c8
--- /dev/null
+++ b/subprojects/callback-manager/include/callback_manager.hpp
@@ -0,0 +1,95 @@
+#pragma once
+
+#include <boost/algorithm/string/predicate.hpp>
+#include <sdbusplus/asio/connection.hpp>
+#include <sdbusplus/asio/object_server.hpp>
+
+#include <iostream>
+
+using Association = std::tuple<std::string, std::string, std::string>;
+
+constexpr const char* rootPath = "/xyz/openbmc_project/CallbackManager";
+constexpr const char* sensorPath = "/xyz/openbmc_project/sensors";
+
+constexpr const char* globalInventoryIface =
+    "xyz.openbmc_project.Inventory.Item.Global";
+constexpr const char* associationIface =
+    "xyz.openbmc_project.Association.Definitions";
+
+namespace threshold
+{
+constexpr const char* critical = "critical";
+constexpr const char* warning = "warning";
+} // namespace threshold
+
+struct AssociationManager
+{
+    AssociationManager(sdbusplus::asio::object_server& objectServerIn,
+                       std::shared_ptr<sdbusplus::asio::connection>& /*conn*/) :
+        objectServer(objectServerIn),
+        association(objectServer.add_interface(rootPath, associationIface)),
+        sensorAssociation(
+            objectServer.add_interface(sensorPath, associationIface))
+    {
+        association->register_property("Associations", std::set<Association>());
+        sensorAssociation->register_property("Associations",
+                                             std::set<Association>());
+        association->initialize();
+        sensorAssociation->initialize();
+    }
+    ~AssociationManager()
+    {
+        objectServer.remove_interface(association);
+        objectServer.remove_interface(sensorAssociation);
+    }
+
+    void setLocalAssociations(const std::vector<std::string>& fatal,
+                              const std::vector<std::string>& critical,
+                              const std::vector<std::string>& warning)
+    {
+        std::set<Association> result;
+
+        // fatal maps to redfish critical as refish only has 3 states and LED
+        // has 4
+        for (const std::string& path : fatal)
+        {
+            result.emplace(threshold::critical, "", path);
+        }
+        for (const std::string& path : critical)
+        {
+            result.emplace(threshold::warning, "", path);
+        }
+        for (const std::string& path : warning)
+        {
+            result.emplace(threshold::warning, "", path);
+        }
+        association->set_property("Associations", result);
+    }
+
+    void setSensorAssociations(const std::vector<std::string>& critical,
+                               const std::vector<std::string>& warning)
+    {
+        std::set<Association> result;
+        for (const std::string& path : critical)
+        {
+            if (!boost::starts_with(path, sensorPath))
+            {
+                continue;
+            }
+            result.emplace(threshold::critical, "", path);
+        }
+        for (const std::string& path : warning)
+        {
+            if (!boost::starts_with(path, sensorPath))
+            {
+                continue;
+            }
+            result.emplace(threshold::warning, "", path);
+        }
+        sensorAssociation->set_property("Associations", result);
+    }
+
+    sdbusplus::asio::object_server& objectServer;
+    std::shared_ptr<sdbusplus::asio::dbus_interface> association;
+    std::shared_ptr<sdbusplus::asio::dbus_interface> sensorAssociation;
+};