diff --git a/devtools/CMakeLists.txt b/devtools/CMakeLists.txt
index e4250d9c..399bb479 100644
--- a/devtools/CMakeLists.txt
+++ b/devtools/CMakeLists.txt
@@ -13,3 +13,6 @@ if(JACK_FOUND AND TARGET Qt5::Widgets)
     target_link_libraries(sfizz_capture_eg PRIVATE sfizz-sndfile Qt5::Widgets ${JACK_LIBRARIES})
     set_target_properties(sfizz_capture_eg PROPERTIES AUTOUIC ON)
 endif()
+
+add_executable(sfizz_preprocessor Preprocessor.cpp)
+target_link_libraries(sfizz_preprocessor sfizz_parser)
diff --git a/devtools/Preprocessor.cpp b/devtools/Preprocessor.cpp
new file mode 100644
index 00000000..f9dbfba6
--- /dev/null
+++ b/devtools/Preprocessor.cpp
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: BSD-2-Clause
+
+// This code is part of the sfizz library and is licensed under a BSD 2-clause
+// license. You should have receive a LICENSE.md file along with the code.
+// If not, contact the sfizz maintainers at https://github.com/sfztools/sfizz
+
+/*
+  This program reads a SFZ file, and outputs it back into a single file
+  with all the includes and definitions processed.
+
+  It can serve to facilitate identifying problems, whether these are related to
+  the parser or complicated instrument structures.
+ */
+
+#include "parser/Parser.h"
+#include "../tests/cxxopts.hpp"
+#include "absl/strings/string_view.h"
+#include <iostream>
+
+class MyParserListener : public sfz::Parser::Listener {
+public:
+    explicit MyParserListener(sfz::Parser& parser)
+        : _parser(parser)
+    {
+    }
+
+protected:
+    void onParseFullBlock(const std::string& header, const std::vector<sfz::Opcode>& opcodes) override
+    {
+        std::cout << '\n';
+        std::cout << '<' << header << '>' << '\n';
+        for (const sfz::Opcode& opc : opcodes)
+            std::cout << opc.opcode << '=' << opc.value << '\n';
+    }
+
+    void onParseError(const sfz::SourceRange& range, const std::string& message) override
+    {
+        const auto relativePath = range.start.filePath->lexically_relative(_parser.originalDirectory());
+        std::cerr << "Parse error in " << relativePath << " at line " << range.start.lineNumber + 1 << ": " << message << '\n';
+    }
+
+    void onParseWarning(const sfz::SourceRange& range, const std::string& message) override
+    {
+        const auto relativePath = range.start.filePath->lexically_relative(_parser.originalDirectory());
+        std::cerr << "Parse warning in " << relativePath << " at line " << range.start.lineNumber + 1 << ": " << message << '\n';
+    }
+
+private:
+    sfz::Parser& _parser;
+};
+
+int main(int argc, char *argv[])
+{
+    cxxopts::Options options("sfizz_preprocess", "Preprocess SFZ files");
+
+    options.positional_help("<sfz-file>");
+
+    options.add_options()
+        ("D,define", "Add external definition", cxxopts::value<std::vector<std::string>>())
+        ("i,input", "Input SFZ file", cxxopts::value<std::string>())
+        ("h,help", "Print usage");
+
+    options.parse_positional({"input"});
+
+    std::unique_ptr<cxxopts::ParseResult> resultPtr;
+    try {
+        resultPtr = absl::make_unique<cxxopts::ParseResult>(options.parse(argc, argv));
+    } catch (cxxopts::OptionException& ex) {
+        std::cerr << ex.what() << "\n";
+        return 1;
+    }
+    cxxopts::ParseResult& result = *resultPtr;
+
+    if (result.count("help")) {
+        std::cerr << options.help() << "\n";
+        return 0;
+    }
+
+    if (!result.count("input")) {
+        std::cerr << "Please indicate the SFZ file path.\n";
+        return 1;
+    }
+
+    const fs::path sfzFilePath { result["input"].as<std::string>() };
+
+    sfz::Parser parser;
+    MyParserListener listener(parser);
+    parser.setListener(&listener);
+
+    if (result.count("define")) {
+        auto& definitions = result["define"].as<std::vector<std::string>>();
+        for (absl::string_view definition : definitions) {
+            size_t pos = definition.find('=');
+            if (pos == definition.npos) {
+                std::cerr << "The definition is malformed, should be key=value.\n";
+                return 1;
+            }
+            absl::string_view key = definition.substr(0, pos);
+            absl::string_view val = definition.substr(pos + 1);
+            parser.addExternalDefinition(key, val);
+        }
+    }
+
+    parser.parseFile(sfzFilePath);
+
+    if (parser.getErrorCount() > 0)
+        return 1;
+
+    return 0;
+}