diff --git a/libdaggy/src/Serialization.cpp b/libdaggy/src/Serialization.cpp
index f3285b2..76bb037 100644
--- a/libdaggy/src/Serialization.cpp
+++ b/libdaggy/src/Serialization.cpp
@@ -121,28 +121,42 @@ namespace daggy {
 
     // Grab the standard fields with defaults;
     if (spec.HasMember("isGenerator")) {
+      if (! spec["isGenerator"].IsBool())
+        throw std::runtime_error("isGenerator must be a boolean value");
       task.isGenerator = spec["isGenerator"].GetBool();
     }
 
     if (spec.HasMember("maxRetries")) {
+      if (! spec["maxRetries"].IsInt())
+        throw std::runtime_error("maxRetries must be an integer");
       task.maxRetries = spec["maxRetries"].GetInt();
     }
 
     if (spec.HasMember("retryIntervalSeconds")) {
+      if (! spec["retryIntervalSeconds"].IsInt())
+        throw std::runtime_error("retryIntervalSeconds must be an integer");
       task.retryIntervalSeconds = spec["retryIntervalSeconds"].GetInt();
     }
 
     // Children / parents
     if (spec.HasMember("children")) {
+      if (! spec["children"].IsArray())
+        throw std::runtime_error("task.children must be specified as an array of strings");
       const auto &specChildren = spec["children"].GetArray();
       for (size_t c = 0; c < specChildren.Size(); ++c) {
+        if (! specChildren[c].IsString())
+          throw std::runtime_error("task.children must be specified as an array of strings");
         task.children.insert(specChildren[c].GetString());
       }
     }
 
     if (spec.HasMember("parents")) {
+      if (! spec["parents"].IsArray())
+        throw std::runtime_error("task.parents must be specified as an array of strings");
       const auto &specParents = spec["parents"].GetArray();
       for (size_t c = 0; c < specParents.Size(); ++c) {
+        if (! specParents[c].IsString())
+          throw std::runtime_error("task.parents must be specified as an array of strings");
         task.parents.insert(specParents[c].GetString());
       }
     }
@@ -154,13 +168,16 @@ namespace daggy {
       for (auto it = params.MemberBegin(); it != params.MemberEnd(); ++it) {
         if (!it->name.IsString())
           throw std::runtime_error("job key must be a string.");
+        auto name = it->name.GetString();
 
         if (it->value.IsArray()) {
           std::vector<std::string> values;
           for (size_t i = 0; i < it->value.Size(); ++i) {
+            if (! it->value[i].IsString())
+              throw std::runtime_error(std::string{"All entries in job."} + name + " must be strings");
             values.emplace_back(it->value[i].GetString());
           }
-          task.job.insert_or_assign(it->name.GetString(), values);
+          task.job.insert_or_assign(name, values);
         }
         else if (it->value.IsString()) {
           task.job.insert_or_assign(it->name.GetString(),