diff --git a/tests/zecsy.c b/tests/zecsy.c
index 05b4087..ae3fa5a 100644
--- a/tests/zecsy.c
+++ b/tests/zecsy.c
@@ -1,3 +1,4 @@
+#include <stdio.h>
 #include <stdlib.h>
 #define CLOVE_IMPLEMENTATION
 #include <clove-unit.h>
@@ -33,7 +34,12 @@ CLOVE_TEST(alive_entities)
 
     entity_id e = make_entity(w);
     CLOVE_SIZET_NE(e, RESERVED_ENTITY_ID);
-    CLOVE_IS_TRUE(world_has_entity(w, e));
+    CLOVE_IS_TRUE(is_alive(w, e));
+
+    archetype_signature sig = arhetype_of(w, e);
+    archetype_signature empty_sig = {0};
+    CLOVE_IS_TRUE(is_same(sig, empty_sig));
+
     destroy_world(&w);
 }
 
@@ -44,7 +50,7 @@ CLOVE_TEST(dead_entities)
 
     entity_id e = make_entity(w);
     destroy_entity(w, e);
-    CLOVE_IS_FALSE(world_has_entity(w, e));
+    CLOVE_IS_FALSE(is_alive(w, e));
 
     destroy_world(&w);
 }
diff --git a/zecsy.h b/zecsy.h
index aedaee5..adf9541 100644
--- a/zecsy.h
+++ b/zecsy.h
@@ -1,17 +1,36 @@
 #ifndef __ZECSY_H
 #define __ZECSY_H
 
+#ifndef ZECSY_MAX_COMPONENTS
+#define ZECSY_MAX_COMPONENTS 128
+#endif // !ZECSY_MAX_COMPONENTS
+
 #define STB_DS_IMPLEMENTATION
 #include "stb_ds.h"
 #include <stdlib.h>
 #include <stddef.h>
+#include <stdint.h>
+
+typedef struct 
+{
+    uint32_t bitset[(ZECSY_MAX_COMPONENTS + 31) / 32];
+} archetype_signature;
 
 #define RESERVED_ENTITY_ID 0
 typedef size_t entity_id;
+typedef size_t component_id;
+
+typedef struct 
+{
+    const char* name;
+    component_id id;
+    size_t size;
+} component_info;
 
 typedef struct
 {
-    struct{entity_id key; int value;}* entity_map; 
+    struct{entity_id key; archetype_signature value;}* entity_map;
+
     entity_id entity_id_counter;
     entity_id alive_entities;
 } world;
@@ -22,7 +41,10 @@ void destroy_world(world** w);
 entity_id make_entity(world* w);
 void destroy_entity(world* w, entity_id e);
 
-int world_has_entity(world* w, entity_id e);
+int is_alive(world* w, entity_id e);
+
+archetype_signature arhetype_of(world* w, entity_id e);
+int is_same(archetype_signature a, archetype_signature b);
 
 #endif // !__ZECSY_H
 
@@ -58,12 +80,14 @@ void destroy_world(world** w)
 
 entity_id make_entity(world* w)
 {
+
     entity_id e = RESERVED_ENTITY_ID;
     
     if(w)
     {
         e = w->entity_id_counter++;
-        hmput(w->entity_map, e, 1);
+
+        hmput(w->entity_map, e, (archetype_signature){0});
         w->alive_entities++;
     }
 
@@ -76,7 +100,7 @@ void destroy_entity(world* w, entity_id e)
         hmdel(w->entity_map, e);
 }
 
-int world_has_entity(world* w, entity_id e)
+int is_alive(world* w, entity_id e)
 {
     if(w)
     {
@@ -86,4 +110,31 @@ int world_has_entity(world* w, entity_id e)
     return 0;
 }
 
+archetype_signature arhetype_of(world* w, entity_id e)
+{
+    if(w)
+    {
+        int index = hmgeti(w->entity_map, e);
+
+        if(index >= 0)
+        {
+            return w->entity_map[index].value;
+        }
+    }
+    return (archetype_signature){0};
+}
+
+int is_same(archetype_signature a, archetype_signature b)
+{
+    for(int i = 0; i < sizeof(a.bitset) / sizeof(a.bitset[0]); ++i)
+    {
+        if(a.bitset[i] != b.bitset[i])
+        {
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
 #endif // ZECSY_IMPLEMENTATION