diff --git a/src/file_io.cpp b/src/file_io.cpp
new file mode 100644
index 0000000..a5be9c3
--- /dev/null
+++ b/src/file_io.cpp
@@ -0,0 +1,66 @@
+#include "file_io.hpp"
+#include "exceptions.hpp"
+#include "util/string.hpp"
+
+#include <algorithm>
+#include <fstream>
+#include <exception>
+#include <functional>
+#include <unordered_map>
+
+namespace gz {
+
+    template<typename Hash, typename Pred>
+    bool writeKeyValueFile(const std::string& filepath, const std::unordered_map<std::string, std::string, Hash, Pred>& content) {
+        bool success = false;
+        std::ofstream file(filepath.c_str());
+        if (file.is_open()) {
+            file << "# Written by writeKeyValueFile" << std::endl;
+            for (std::pair<std::string, std::string> line : content) {
+                file << line.first << " = " << line.second << std::endl;
+            }
+            file.close();
+            success = true;
+        }
+        else {
+            throw FileIOError("Could not open file: '" + filepath + "'", "writeKeyValueFile");
+        }
+        return success;
+    }
+
+    std::unordered_map<std::string, std::string> readKeyValueFile(const std::string& filepath, bool removeSpaces) {
+        std::unordered_map<std::string, std::string> attr;
+        std::string line;
+        int eqPos;
+        std::ifstream file(filepath);
+        if (file.is_open()) {
+            while (file.good()) {
+                getline(file, line);
+
+                // ignore commented lines
+                if (line.find("#") != std::string::npos) { continue; }
+
+                // if "=" in line: split into key - value pair and store in map
+                if (line.find("=") != std::string::npos) {
+                    if (removeSpaces) {  // remove all whitespaces
+                        line.erase(std::remove_if(line.begin(), line.end(), [](unsigned char x) { return std::isspace(x); }), line.end()); 
+                    }
+                    else {  // remove whitespaces until after equal sign
+                        eqPos = line.find("=");
+                        line.erase(std::remove_if(line.begin(), line.begin() + eqPos + 2, [](unsigned char x) { return std::isspace(x); }), line.begin() + eqPos + 2);
+                    }
+                    eqPos = line.find("=");
+                    attr[line.substr(0, eqPos)] = line.substr(eqPos+1, line.length());
+                }
+            }
+            file.close();
+        }
+        else {
+            throw FileIOError("Could not open file: '" + filepath + "'", "readKeyValueFile");
+        }
+        return attr;
+    }
+
+    template bool writeKeyValueFile<std::hash<std::string>, std::equal_to<std::string>>(const std::string&, const std::unordered_map<std::string, std::string, std::hash<std::string>, std::equal_to<std::string>>&);
+    template bool writeKeyValueFile<util::string_hash, std::equal_to<>>(const std::string&, const std::unordered_map<std::string, std::string, util::string_hash, std::equal_to<>>&);
+}
diff --git a/src/file_io.hpp b/src/file_io.hpp
new file mode 100644
index 0000000..b43ce67
--- /dev/null
+++ b/src/file_io.hpp
@@ -0,0 +1,24 @@
+#pragma once
+
+#include "util/string.hpp"
+#include "util/string_conversion.hpp"
+
+
+namespace gz {
+
+    /**
+     * @brief Write a file that contains key = value pairs
+     * @details
+     *  This template function is instantiated for the default unordered_map<string, string> and the util::string_map from util/string.hpp
+     * @throws FileIOError
+     */
+    template<typename Hash, typename Pred>
+    bool writeKeyValueFile(const std::string& filepath, const std::unordered_map<std::string, std::string, Hash, Pred>& content);
+
+    /**
+     * @brief Read a file that contains key = value pairs
+     * @throws FileIOError
+     */
+    std::unordered_map<std::string, std::string> readKeyValueFile(const std::string& filepath, bool removeSpaces=false);
+
+}