diff --git a/examples/14_json_template.cpp b/examples/14_json_template.cpp
index 2641731d02..1e1a26e2a0 100644
--- a/examples/14_json_template.cpp
+++ b/examples/14_json_template.cpp
@@ -2,10 +2,15 @@
 
 int main()
 {
+    std::string config = R"(
+iteration_encoding = "variable_based"
+
+[json]
+mode = "template"
+)";
+
     openPMD::Series writeTemplate(
-        "../samples/jsonTemplate.json",
-        openPMD::Access::CREATE,
-        R"(iteration_encoding = "variable_based")");
+        "../samples/jsonTemplate.json", openPMD::Access::CREATE, config);
     auto iteration = writeTemplate.writeIterations()[0];
 
     auto temperature =
diff --git a/include/openPMD/IO/JSON/JSONIOHandler.hpp b/include/openPMD/IO/JSON/JSONIOHandler.hpp
index 37b00fa165..3c593afb42 100644
--- a/include/openPMD/IO/JSON/JSONIOHandler.hpp
+++ b/include/openPMD/IO/JSON/JSONIOHandler.hpp
@@ -23,13 +23,15 @@
 
 #include "openPMD/IO/AbstractIOHandler.hpp"
 #include "openPMD/IO/JSON/JSONIOHandlerImpl.hpp"
+#include "openPMD/auxiliary/JSON_internal.hpp"
 
 namespace openPMD
 {
 class JSONIOHandler : public AbstractIOHandler
 {
 public:
-    JSONIOHandler(std::string path, Access at);
+    JSONIOHandler(
+        std::string path, Access at, openPMD::json::TracingJSON config);
 
     ~JSONIOHandler() override;
 
diff --git a/include/openPMD/IO/JSON/JSONIOHandlerImpl.hpp b/include/openPMD/IO/JSON/JSONIOHandlerImpl.hpp
index c7ad57a6b9..6d1b8bdc01 100644
--- a/include/openPMD/IO/JSON/JSONIOHandlerImpl.hpp
+++ b/include/openPMD/IO/JSON/JSONIOHandlerImpl.hpp
@@ -26,6 +26,7 @@
 #include "openPMD/IO/Access.hpp"
 #include "openPMD/IO/JSON/JSONFilePosition.hpp"
 #include "openPMD/auxiliary/Filesystem.hpp"
+#include "openPMD/auxiliary/JSON_internal.hpp"
 #include "openPMD/config.hpp"
 
 #include <nlohmann/json.hpp>
@@ -153,7 +154,8 @@ class JSONIOHandlerImpl : public AbstractIOHandlerImpl
     using json = nlohmann::json;
 
 public:
-    explicit JSONIOHandlerImpl(AbstractIOHandler *);
+    explicit JSONIOHandlerImpl(
+        AbstractIOHandler *, openPMD::json::TracingJSON config);
 
     ~JSONIOHandlerImpl() override;
 
@@ -230,7 +232,7 @@ class JSONIOHandlerImpl : public AbstractIOHandlerImpl
         Template
     };
 
-    IOMode m_mode = IOMode::Template;
+    IOMode m_mode = IOMode::Dataset;
 
     // HELPER FUNCTIONS
 
diff --git a/src/IO/AbstractIOHandlerHelper.cpp b/src/IO/AbstractIOHandlerHelper.cpp
index 22fa6af60f..31ebdeed60 100644
--- a/src/IO/AbstractIOHandlerHelper.cpp
+++ b/src/IO/AbstractIOHandlerHelper.cpp
@@ -115,7 +115,7 @@ std::shared_ptr<AbstractIOHandler> createIOHandler<json::TracingJSON>(
             "ADIOS2", path, access, std::move(options), "ssc");
     case Format::JSON:
         return constructIOHandler<JSONIOHandler, openPMD_HAVE_JSON>(
-            "JSON", path, access);
+            "JSON", path, access, std::move(options));
     default:
         throw std::runtime_error(
             "Unknown file format! Did you specify a file ending?");
diff --git a/src/IO/JSON/JSONIOHandler.cpp b/src/IO/JSON/JSONIOHandler.cpp
index 15d18194c7..c0a16f2077 100644
--- a/src/IO/JSON/JSONIOHandler.cpp
+++ b/src/IO/JSON/JSONIOHandler.cpp
@@ -25,8 +25,9 @@ namespace openPMD
 {
 JSONIOHandler::~JSONIOHandler() = default;
 
-JSONIOHandler::JSONIOHandler(std::string path, Access at)
-    : AbstractIOHandler{path, at}, m_impl{JSONIOHandlerImpl{this}}
+JSONIOHandler::JSONIOHandler(
+    std::string path, Access at, openPMD::json::TracingJSON jsonCfg)
+    : AbstractIOHandler{path, at}, m_impl{this, std::move(jsonCfg)}
 {}
 
 std::future<void> JSONIOHandler::flush(internal::FlushParams const &)
diff --git a/src/IO/JSON/JSONIOHandlerImpl.cpp b/src/IO/JSON/JSONIOHandlerImpl.cpp
index 17253eca76..5d9a7e83dc 100644
--- a/src/IO/JSON/JSONIOHandlerImpl.cpp
+++ b/src/IO/JSON/JSONIOHandlerImpl.cpp
@@ -54,9 +54,62 @@ namespace openPMD
             throw std::runtime_error((TEXT));                                  \
     }
 
-JSONIOHandlerImpl::JSONIOHandlerImpl(AbstractIOHandler *handler)
+JSONIOHandlerImpl::JSONIOHandlerImpl(
+    AbstractIOHandler *handler, openPMD::json::TracingJSON config)
     : AbstractIOHandlerImpl(handler)
-{}
+{
+    if (config.json().contains("json"))
+    {
+        auto jsonConfig = config["json"];
+        if (jsonConfig.json().contains("mode"))
+        {
+            auto modeOption = openPMD::json::asLowerCaseStringDynamic(
+                jsonConfig["mode"].json());
+            if (!modeOption.has_value())
+            {
+                throw error::BackendConfigSchema(
+                    {"json", "mode"},
+                    "Invalid value of non-string type (accepted values are "
+                    "'dataset' and 'template'.");
+            }
+            auto mode = modeOption.value();
+            if (mode == "dataset")
+            {
+                m_mode = IOMode::Dataset;
+            }
+            else if (mode == "template")
+            {
+                m_mode = IOMode::Template;
+            }
+            else
+            {
+                throw error::BackendConfigSchema(
+                    {"json", "mode"},
+                    "Invalid value: '" + mode +
+                        "' (accepted values are 'dataset' and 'template'.");
+            }
+        }
+        auto shadow = jsonConfig.invertShadow();
+        if (shadow.size() > 0)
+        {
+            switch (jsonConfig.originallySpecifiedAs)
+            {
+            case openPMD::json::SupportedLanguages::JSON:
+                std::cerr << "Warning: parts of the backend configuration for "
+                             "JSON backend remain unused:\n"
+                          << shadow << std::endl;
+                break;
+            case openPMD::json::SupportedLanguages::TOML: {
+                auto asToml = openPMD::json::jsonToToml(shadow);
+                std::cerr << "Warning: parts of the backend configuration for "
+                             "JSON backend remain unused:\n"
+                          << asToml << std::endl;
+                break;
+            }
+            }
+        }
+    }
+}
 
 JSONIOHandlerImpl::~JSONIOHandlerImpl()
 {