diff --git a/slsDetectorSoftware/tests/master_file/Context.h b/slsDetectorSoftware/tests/master_file/Context.h
index b597ac19f..e5fd13048 100644
--- a/slsDetectorSoftware/tests/master_file/Context.h
+++ b/slsDetectorSoftware/tests/master_file/Context.h
@@ -13,7 +13,7 @@
 namespace sls::test::master_file {
 
 struct JsonContext {
-    const rapidjson::Document doc;
+    rapidjson::Document doc;
 };
 #ifdef HDF5C
 struct H5Context {
diff --git a/slsDetectorSoftware/tests/master_file/Readers.cpp b/slsDetectorSoftware/tests/master_file/Readers.cpp
index a97932ec0..d9e14745c 100644
--- a/slsDetectorSoftware/tests/master_file/Readers.cpp
+++ b/slsDetectorSoftware/tests/master_file/Readers.cpp
@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: LGPL-3.0-or-other
 // Copyright (C) 2021 Contributors to the SLS Detector Package
 #include "Readers.h"
-#include "Context.h"
 
 #include "sls/ToString.h"
 
diff --git a/slsDetectorSoftware/tests/master_file/Readers.h b/slsDetectorSoftware/tests/master_file/Readers.h
index 71d2e8f7c..84b160fb9 100644
--- a/slsDetectorSoftware/tests/master_file/Readers.h
+++ b/slsDetectorSoftware/tests/master_file/Readers.h
@@ -2,152 +2,20 @@
 // Copyright (C) 2021 Contributors to the SLS Detector Package
 #pragma once
 
-#include "sls/sls_detector_defs.h"
+#include "Context.h"
 
 #ifdef HDF5C
 #include "H5Cpp.h"
 #endif
 
-#include <array>
-#include <map>
 #include <rapidjson/document.h>
-#include <string>
-#include <vector>
 
 namespace sls::test::master_file {
-using ns = std::chrono::nanoseconds;
-using rapidjson::Document;
+template <typename Context, typename T> struct Reader;
 
-/*
-struct JsonDoc {
-    const rapidjson::Document &doc;
-};
-#ifdef HDF5C
-struct H5Doc {
-    const H5::DataSet& ds;
-};
-#endif
-
-template <typename doc, typename T>
-T read(const doc& b, const std::string& name);
-*/
-
-/** ---scalar reads--- */
-/** std::string */
-/*
-template <>
-inline std::string read<JsonDoc, std::string>(
-    const JsonDoc& b,
-    const std::string& name)
-{
-        return b.doc[name.c_str()].GetString();
+template <typename Context, typename T>
+T read(const Context &ctx, const std::string &name) {
+    return Reader<Context, T>::read(ctx, name);
 }
-#ifdef HDF5C
-template <>
-inline std::string read<H5Doc, std::string>(
-    const H5Doc& b,
-    const std::string& name)
-{
-    std::string out;
-    b.ds.read(out, ds.getStrType());
-    return out;
-}
-#endif
-*/
-void read_from_json(const Document &doc, const std::string &name,
-                    std::string &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          std::string &out);
-#endif
-
-/** int */
-void read_from_json(const Document &doc, const std::string &name, int &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          int &out);
-#endif
-
-/** uint32_t */
-void read_from_json(const Document &doc, const std::string &name,
-                    uint32_t &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          uint32_t &out);
-#endif
-
-/** uint64_t */
-void read_from_json(const Document &doc, const std::string &name,
-                    uint64_t &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          uint64_t &out);
-#endif
-
-/** double */
-void read_from_json(const Document &doc, const std::string &name, double &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          double &out);
-#endif
-
-/* ---vector reads--- */
-/** int64_t */
-void read_from_json(const Document &doc, const std::string &name,
-                    std::vector<int64_t> &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          std::vector<int64_t> &out);
-#endif
-
-/* ---arrays/ maps--- */
-/** std::array<int, 3UL> */
-void read_from_json(const Document &doc, const std::string &name,
-                    std::array<int, 3UL> &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          std::array<int, 3UL> &out);
-#endif
-
-/** std::array<ns, 3UL> */
-void read_from_json(const Document &doc, const std::string &name,
-                    std::array<ns, 3UL> &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          std::array<ns, 3UL> &out);
-#endif
-
-/** std::map<std::string, std::string> */
-void read_from_json(const Document &doc, const std::string &name,
-                    std::map<std::string, std::string> &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          std::map<std::string, std::string> &out);
-#endif
-
-/* complex types */
-/* std::vector<ROI> */
-void read_from_json(const Document &doc, const std::string &name,
-                    std::vector<defs::ROI> &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          std::vector<defs::ROI> &out);
-#endif
-
-/** defs::xy */
-void read_from_json(const Document &doc, const std::string &name,
-                    defs::xy &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          defs::xy &out);
-#endif
-
-/** defs::scanParameters */
-void read_from_json(const Document &doc, const std::string &name,
-                    defs::scanParameters &out);
-#ifdef HDF5C
-void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
-                          defs::scanParameters &out);
-#endif
 
 } // namespace sls::test::master_file
diff --git a/slsDetectorSoftware/tests/master_file/ReadersH5.cpp b/slsDetectorSoftware/tests/master_file/ReadersH5.cpp
new file mode 100644
index 000000000..647197b6b
--- /dev/null
+++ b/slsDetectorSoftware/tests/master_file/ReadersH5.cpp
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: LGPL-3.0-or-other
+// Copyright (C) 2021 Contributors to the SLS Detector Package
+
+#include "Readers.h"
+
+#ifdef HDF5C
+
+namespace sls::test::master_file {
+
+template <>
+struct Reader<H5Context, int> {
+
+    static int read(const H5Context& ctx,
+                    const std::string& name) {
+
+        auto ds = ctx.file.openDataSet(HDF5_GROUP + name);
+        int out{};
+        ds.read(&out, H5::PredType::NATIVE_INT);
+        return out;
+    }
+};
+
+} // namespace sls::test::master_file
+
+#endif
\ No newline at end of file
diff --git a/slsDetectorSoftware/tests/master_file/ReadersJson.cpp b/slsDetectorSoftware/tests/master_file/ReadersJson.cpp
new file mode 100644
index 000000000..5fb2c7584
--- /dev/null
+++ b/slsDetectorSoftware/tests/master_file/ReadersJson.cpp
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: LGPL-3.0-or-other
+// Copyright (C) 2021 Contributors to the SLS Detector Package
+
+#include "Readers.h"
+
+namespace sls::test::master_file {
+
+/* --scalar reads-- */
+template <>
+struct Reader<JsonContext, int> {
+    static int read(const JsonContext &ctx, const std::string &name) {
+        return ctx.doc[name.c_str()].GetInt();
+    }
+};
+
+template<>
+struct Reader<JsonContext, uint32_t> {
+
+    static uint32_t read(const JsonContext& ctx,
+                         const std::string& name) {
+
+        return ctx.doc[name.c_str()].GetUint();
+
+    }
+};
+
+template<>
+struct Reader<JsonContext, uint64_t> {
+
+    static uint64_t read(const JsonContext& ctx,
+                         const std::string& name) {
+
+        return ctx.doc[name.c_str()].GetUint64();
+    }
+};
+
+template<>
+struct Reader<JsonContext, double> {
+
+    static double read(const JsonContext& ctx,
+                       const std::string& name) {
+
+        return ctx.doc[name.c_str()].GetDouble();
+    }
+};
+
+template<>
+struct Reader<JsonContext, std::string> {
+
+    static std::string read(const JsonContext& ctx,
+                            const std::string& name) {
+
+        return ctx.doc[name.c_str()].GetString();
+    }
+};
+
+} // namespace sls::test::master_file
\ No newline at end of file
diff --git a/slsDetectorSoftware/tests/master_file/Readers_bak.h b/slsDetectorSoftware/tests/master_file/Readers_bak.h
new file mode 100644
index 000000000..864501068
--- /dev/null
+++ b/slsDetectorSoftware/tests/master_file/Readers_bak.h
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: LGPL-3.0-or-other
+// Copyright (C) 2021 Contributors to the SLS Detector Package
+#pragma once
+
+#include "Context.h"
+#include "sls/sls_detector_defs.h"
+
+#ifdef HDF5C
+#include "H5Cpp.h"
+#endif
+
+#include <rapidjson/document.h>
+
+namespace sls::test::master_file {
+
+using ns = std::chrono::nanoseconds;
+
+void read_from_json(const Document &doc, const std::string &name,
+                    std::string &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          std::string &out);
+#endif
+
+/** int */
+void read_from_json(const Document &doc, const std::string &name, int &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          int &out);
+#endif
+
+/** uint32_t */
+void read_from_json(const Document &doc, const std::string &name,
+                    uint32_t &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          uint32_t &out);
+#endif
+
+/** uint64_t */
+void read_from_json(const Document &doc, const std::string &name,
+                    uint64_t &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          uint64_t &out);
+#endif
+
+/** double */
+void read_from_json(const Document &doc, const std::string &name, double &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          double &out);
+#endif
+
+/* ---vector reads--- */
+/** int64_t */
+void read_from_json(const Document &doc, const std::string &name,
+                    std::vector<int64_t> &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          std::vector<int64_t> &out);
+#endif
+
+/* ---arrays/ maps--- */
+/** std::array<int, 3UL> */
+void read_from_json(const Document &doc, const std::string &name,
+                    std::array<int, 3UL> &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          std::array<int, 3UL> &out);
+#endif
+
+/** std::array<ns, 3UL> */
+void read_from_json(const Document &doc, const std::string &name,
+                    std::array<ns, 3UL> &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          std::array<ns, 3UL> &out);
+#endif
+
+/** std::map<std::string, std::string> */
+void read_from_json(const Document &doc, const std::string &name,
+                    std::map<std::string, std::string> &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          std::map<std::string, std::string> &out);
+#endif
+
+/* complex types */
+/* std::vector<ROI> */
+void read_from_json(const Document &doc, const std::string &name,
+                    std::vector<defs::ROI> &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          std::vector<defs::ROI> &out);
+#endif
+
+/** defs::xy */
+void read_from_json(const Document &doc, const std::string &name,
+                    defs::xy &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          defs::xy &out);
+#endif
+
+/** defs::scanParameters */
+void read_from_json(const Document &doc, const std::string &name,
+                    defs::scanParameters &out);
+#ifdef HDF5C
+void read_from_h5_dataset(const H5::DataSet &ds, const std::string &name,
+                          defs::scanParameters &out);
+#endif
+
+} // namespace sls::test::master_file