diff --git a/libdevcore/JSON.h b/libdevcore/JSON.h
index 7876dfb21..0d6e0d2e8 100644
--- a/libdevcore/JSON.h
+++ b/libdevcore/JSON.h
@@ -28,13 +28,13 @@ namespace dev
 {
 
 /// Serialise the JSON object (@a _input) with identation
-std::string jsonPrettyPrint(Json::Value const& _input)
+inline std::string jsonPrettyPrint(Json::Value const& _input)
 {
 	return Json::StyledWriter().write(_input);
 }
 
 /// Serialise theJ SON object (@a _input) without identation
-std::string jsonCompactPrint(Json::Value const& _input)
+inline std::string jsonCompactPrint(Json::Value const& _input)
 {
 	Json::FastWriter writer;
 	writer.omitEndingLineFeed();