diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 7f44276bd..3ac9c20f9 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -14,6 +14,7 @@
 #include "worker-protocol.hh"
 #include "topo-sort.hh"
 #include "callback.hh"
+#include "json-utils.hh"
 
 #include <regex>
 #include <queue>
@@ -56,8 +57,6 @@
 #include <pwd.h>
 #include <grp.h>
 
-#include <nlohmann/json.hpp>
-
 namespace nix {
 
 void handleDiffHook(
diff --git a/src/libutil/json-utils.hh b/src/libutil/json-utils.hh
new file mode 100644
index 000000000..b8a031227
--- /dev/null
+++ b/src/libutil/json-utils.hh
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <nlohmann/json.hpp>
+
+namespace nix {
+
+const nlohmann::json * get(const nlohmann::json & map, const std::string & key)
+{
+    auto i = map.find(key);
+    if (i == map.end()) return nullptr;
+    return &*i;
+}
+
+nlohmann::json * get(nlohmann::json & map, const std::string & key)
+{
+    auto i = map.find(key);
+    if (i == map.end()) return nullptr;
+    return &*i;
+}
+
+}
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 8bc99f531..d4d78329d 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -1586,23 +1586,8 @@ std::string stripIndentation(std::string_view s)
 }
 
 
-const nlohmann::json * get(const nlohmann::json & map, const std::string & key)
-{
-    auto i = map.find(key);
-    if (i == map.end()) return nullptr;
-    return &*i;
-}
-
-nlohmann::json * get(nlohmann::json & map, const std::string & key)
-{
-    auto i = map.find(key);
-    if (i == map.end()) return nullptr;
-    return &*i;
-}
-
 //////////////////////////////////////////////////////////////////////
 
-
 static Sync<std::pair<unsigned short, unsigned short>> windowSize{{0, 0}};
 
 
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 6319ced47..09ccfa591 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -558,9 +558,6 @@ typename T::mapped_type * get(T & map, const typename T::key_type & key)
     return &i->second;
 }
 
-const nlohmann::json * get(const nlohmann::json & map, const std::string & key);
-nlohmann::json * get(nlohmann::json & map, const std::string & key);
-
 /* Get a value for the specified key from an associate container, or a default value if the key isn't present. */
 template <class T>
 const typename T::mapped_type & getOr(T & map,