diff --git a/build/buildjson.cpp b/build/buildjson.cpp
new file mode 100644
index 0000000..a5ae502
--- /dev/null
+++ b/build/buildjson.cpp
@@ -0,0 +1,64 @@
+#include "build/buildjson.hpp"
+
+#include "errors/exception.hpp"
+
+#include <fstream>
+#include <nlohmann/json.hpp>
+
+using json = nlohmann::json;
+
+void validateJson(const json& data)
+{
+    if (data.count("sensors") != 1)
+    {
+        throw ConfigurationException(
+            "KeyError: 'sensors' not found (or found repeatedly)");
+    }
+
+    if (data["sensors"].size() == 0)
+    {
+        throw ConfigurationException(
+            "Invalid Configuration: At least one sensor required");
+    }
+
+    if (data.count("zones") != 1)
+    {
+        throw ConfigurationException(
+            "KeyError: 'zones' not found (or found repeatedly)");
+    }
+
+    for (const auto& zone : data["zones"])
+    {
+        if (zone.count("pids") != 1)
+        {
+            throw ConfigurationException(
+                "KeyError: should only have one 'pids' key per zone.");
+        }
+
+        if (zone["pids"].size() == 0)
+        {
+            throw ConfigurationException(
+                "Invalid Configuration: must be at least one pid per zone.");
+        }
+    }
+}
+
+json parseValidateJson(const std::string& path)
+{
+    std::ifstream jsonFile(path);
+    if (!jsonFile.is_open())
+    {
+        throw ConfigurationException("Unable to open json file");
+    }
+
+    auto data = json::parse(jsonFile, nullptr, false);
+    if (data.is_discarded())
+    {
+        throw ConfigurationException("Invalid json - parse failed");
+    }
+
+    /* Check the data. */
+    validateJson(data);
+
+    return data;
+}
diff --git a/build/buildjson.hpp b/build/buildjson.hpp
new file mode 100644
index 0000000..afc90df
--- /dev/null
+++ b/build/buildjson.hpp
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <nlohmann/json.hpp>
+#include <string>
+
+using json = nlohmann::json;
+
+/**
+ * Given json data, validate the minimum.
+ * The json data must be valid, and must contain two keys:
+ * sensors, and zones.
+ *
+ * @param[in] data - the json data.
+ * @return nothing - throws exceptions on invalid bits.
+ */
+void validateJson(const json& data);
+
+/**
+ * Given a json configuration file, parse it.
+ *
+ * There must be at least one sensor, and one zone.
+ * That one zone must contain at least one PID.
+ *
+ * @param[in] path - path to the configuration
+ * @return the json data.
+ */
+json parseValidateJson(const std::string& path);