diff --git a/src/lib/seallib/assert.cpp b/src/lib/seallib/assert.cpp
new file mode 100644
index 0000000..d49c5c5
--- /dev/null
+++ b/src/lib/seallib/assert.cpp
@@ -0,0 +1,59 @@
+#include "assert.h"
+
+#include <iostream>
+#include <string>
+
+#ifdef _WIN32
+    // from: WinUser.h
+    #ifndef MB_ICONHAND
+        #define MB_ICONHAND 0x00000010L
+        #define MB_ICONERROR MB_ICONHAND
+
+        #define MB_SYSTEMMODAL 0x00001000L
+
+        #define MB_OK 0x00000000L
+    #endif
+
+extern "C"
+{
+    __declspec(dllimport) void* __stdcall GetModuleHandleA(const char* lpModuleName);
+    __declspec(dllimport) void* __stdcall LoadLibraryA(const char* lpLibFileName);
+    __declspec(dllimport) int(__stdcall* __stdcall GetProcAddress(void* hModule, const char* lpProcName))();
+}
+#endif
+
+#ifdef __linux
+    #include <cstdlib>
+#endif
+
+std::string safeShellEscape(const std::string& input)
+{
+    std::string escaped;
+    for (char c : input)
+    {
+        if (c == '"' || c == '\\' || c == '`' || c == '$') escaped += '\\';
+        escaped += c;
+    }
+    return escaped;
+}
+
+void seallib::displayError(const char* msg, const char* file, int line)
+{
+    std::string fullError = std::string(msg) + "\n\nFile: " + file + "\nLine: " + std::to_string(line);
+    std::cerr << "[FATAL ERROR] " << fullError << std::endl;
+
+#ifdef _WIN32
+    typedef int(__stdcall * fnMessageBoxA)(void*, const char*, const char*, unsigned int);
+    if (void* hUser32 = GetModuleHandleA("user32.dll") ? GetModuleHandleA("user32.dll") : LoadLibraryA("user32.dll"))
+    {
+        auto msgBoxA = reinterpret_cast<fnMessageBoxA>(GetProcAddress(hUser32, "MessageBoxA"));
+        if (msgBoxA) msgBoxA(nullptr, fullError.c_str(), "Fatal Error Occurred", MB_ICONERROR | MB_OK | MB_SYSTEMMODAL);
+    }
+#elif __linux__
+    std::string safeMsg = safeShellEscape(fullError);
+    if (std::system("which zenity > /dev/null 2>&1") == 0)
+        std::system(("zenity --error --text=\"" + safeMsg + "\" --title=\"Fatal Error\" 2>/dev/null").c_str());
+    else if (std::system("which kdialog > /dev/null 2>&1") == 0)
+        std::system(("kdialog --error \"" + safeMsg + "\" 2>/dev/null").c_str());
+#endif
+}
diff --git a/src/lib/seallib/assert.h b/src/lib/seallib/assert.h
new file mode 100644
index 0000000..73b2d1f
--- /dev/null
+++ b/src/lib/seallib/assert.h
@@ -0,0 +1,51 @@
+#pragma once
+
+#if defined(_MSC_VER)
+    #define SEALLIB_DEBUGBREAK() __debugbreak()
+    #define SEALLIB_ASSUME(cond) __assume(cond)
+#elif defined(__GNUC__) || defined(__clang__)
+    #define SEALLIB_DEBUGBREAK() __builtin_trap()
+    #define SEALLIB_ASSUME(cond)                                                                                       \
+        do                                                                                                             \
+        {                                                                                                              \
+            if (!(cond)) __builtin_unreachable();                                                                      \
+        } while (0)
+#else
+    #define SEALLIB_DEBUGBREAK()                                                                                       \
+        do                                                                                                             \
+        {                                                                                                              \
+        } while (0)
+    #define SEALLIB_ASSUME(cond)                                                                                       \
+        do                                                                                                             \
+        {                                                                                                              \
+        } while (0)
+#endif
+
+#ifdef _DEBUG
+    #define ASSERT(cond, msg)                                                                                          \
+        do                                                                                                             \
+        {                                                                                                              \
+            if (!(cond))                                                                                               \
+            {                                                                                                          \
+                seallib::displayError(msg, __FILE__, __LINE__);                                                        \
+                SEALLIB_DEBUGBREAK();                                                                                  \
+                std::exit(EXIT_FAILURE);                                                                               \
+            }                                                                                                          \
+            SEALLIB_ASSUME(cond);                                                                                      \
+        } while (0)
+#else
+    #define ASSERT(cond, msg) SEALLIB_ASSUME(cond)
+#endif
+
+#define PANIC(msg)                                                                                                     \
+    do                                                                                                                 \
+    {                                                                                                                  \
+        seallib::displayError(msg, __FILE__, __LINE__);                                                                \
+        SEALLIB_DEBUGBREAK();                                                                                          \
+        std::exit(EXIT_FAILURE);                                                                                       \
+    } while (0)
+
+namespace seallib
+{
+    void displayError(const char* msg, const char* file, int line);
+}