diff --git a/daggy/include/daggy/AttemptRecord.hpp b/daggy/include/daggy/AttemptRecord.hpp
index e7f5cdb..68acb3d 100644
--- a/daggy/include/daggy/AttemptRecord.hpp
+++ b/daggy/include/daggy/AttemptRecord.hpp
@@ -3,12 +3,12 @@
 #include <chrono>
 #include <string>
 
-namespace daggy {
-    using Clock = std::chrono::system_clock;
+#include "Defines.hpp"
 
+namespace daggy {
     struct AttemptRecord {
-        std::chrono::time_point<Clock> startTime;
-        std::chrono::time_point<Clock> stopTime;
+        TimePoint startTime;
+        TimePoint stopTime;
         int rc;       // RC from the task
         std::string metaLog;  // Logs from the executor
         std::string output;   // stdout from command
diff --git a/daggy/include/daggy/Defines.hpp b/daggy/include/daggy/Defines.hpp
new file mode 100644
index 0000000..cf7998b
--- /dev/null
+++ b/daggy/include/daggy/Defines.hpp
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <unordered_map>
+#include <variant>
+
+namespace daggy {
+    // Commands and parameters
+    using ParameterValue = std::variant<std::string, std::vector<std::string>>;
+    using ParameterValues = std::unordered_map<std::string, ParameterValue>;
+    using Command = std::vector<std::string>;
+
+    // Time
+    using Clock = std::chrono::system_clock;
+    using TimePoint = std::chrono::time_point<Clock>;
+
+    // DAG Runs
+    using DAGDefID = int16_t;
+    using DAGRunID = size_t;
+}
diff --git a/daggy/include/daggy/Serialization.h b/daggy/include/daggy/Serialization.h
new file mode 100644
index 0000000..c19e7a4
--- /dev/null
+++ b/daggy/include/daggy/Serialization.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <vector>
+#include <string>
+#include <variant>
+#include <unordered_map>
+
+#include <rapidjson/document.h>
+
+#include "Logger.hpp"
+#include "TaskExecutor.hpp"
+#include "Task.hpp"
+
+namespace rj = rapidjson;
+
+namespace daggy {
+    ParameterValues parseParameters(const std::string & jsonSpec);
+    ParameterValues parseParameters(const rj::Document & spec);
+    std::vector<Task> buildTasks(const std::string & jsonSpec, const ParameterValues & parameters = {});
+    std::vector<Task> buildTasks(const rj::Document & spec, const ParameterValues & parameters = {});
+    std::vector<Command> expandCommands(const std::vector<std::string> & command, const ParameterValues & parameters);
+}
diff --git a/daggy/include/daggy/Utilities.hpp b/daggy/include/daggy/Utilities.hpp
index e315883..0f46bb6 100644
--- a/daggy/include/daggy/Utilities.hpp
+++ b/daggy/include/daggy/Utilities.hpp
@@ -10,22 +10,9 @@
 #include "Logger.hpp"
 #include "TaskExecutor.hpp"
 #include "Task.hpp"
-#include "ThreadPool.hpp"
-
-namespace rj = rapidjson;
+#include "Defines.hpp"
 
 namespace daggy {
-    using ParameterValue = std::variant<std::string, std::vector<std::string>>;
-    using ParameterValues = std::unordered_map<std::string, ParameterValue>;
-    using Command = std::vector<std::string>;
-
-    // Dealing with JSON
-    ParameterValues parseParameters(const std::string & jsonSpec);
-    ParameterValues parseParameters(const rj::Document & spec);
-    std::vector<Task> buildTasks(const std::string & jsonSpec, const ParameterValues & parameters = {});
-    std::vector<Task> buildTasks(const rj::Document & spec, const ParameterValues & parameters = {});
-    std::vector<Command> expandCommands(const std::vector<std::string> & command, const ParameterValues & parameters);
-
     // DAG execution
     // DAG vertex IDs should correspond to the position of tasks in vector. e.g. Vertex ID 0 corresponds to tasks[0]
     // I'm not crazy about this loose coupling, but