diff --git a/Include/Fledasty/Strings/UTF8String.h b/Include/Fledasty/Strings/UTF8String.h
index a75699d..291953f 100644
--- a/Include/Fledasty/Strings/UTF8String.h
+++ b/Include/Fledasty/Strings/UTF8String.h
@@ -56,4 +56,4 @@ FledastyUtf8String fledasty_utf8_string_encode(const uint32_t *unicode, const si
 uint32_t *fledasty_utf8_string_decode(const FledastyUtf8String *current_string, size_t *unicode_string_size);
 
 bool fledasty_utf8_string_validate(unsigned char *character_string, const size_t character_string_size);
-size_t fledasty_utf8_string_get_size(const unsigned char *character_string);
\ No newline at end of file
+size_t fledasty_utf8_string_get_size(const unsigned char *character_string);
diff --git a/Include/Fledasty/Utils/Error.h b/Include/Fledasty/Utils/Error.h
index e9841fd..ce48894 100644
--- a/Include/Fledasty/Utils/Error.h
+++ b/Include/Fledasty/Utils/Error.h
@@ -33,4 +33,4 @@ typedef enum {
     FLEDASTY_ERROR_INVALID_VALUE = 6,
 } FledastyError;
 
-#endif
\ No newline at end of file
+#endif
diff --git a/Src/Strings/UTF8String.c b/Src/Strings/UTF8String.c
index 3d18f49..c4a86d2 100644
--- a/Src/Strings/UTF8String.c
+++ b/Src/Strings/UTF8String.c
@@ -60,8 +60,7 @@ FledastyError fledasty_utf8_string_destroy(FledastyUtf8String *current_string) {
         return FLEDASTY_ERROR_INVALID_POINTER;
     }
     
-    HallocyError result = hallocy_free(current_string->character_string);
-    if (result != HALLOCY_ERROR_NONE) {
+    if (hallocy_free(current_string->character_string) != HALLOCY_ERROR_NONE) {
         return FLEDASTY_ERROR_FAILED_ALLOCATION;
     }
 
@@ -79,11 +78,11 @@ FledastyError fledasty_utf8_string_append(FledastyUtf8String *current_string, un
     }
 
     if (current_string->capacity <= current_string->size + character_string_size) {
-        current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size;
+        current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size + 1;
         current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));
     }
 
-    hallocy_copy_memory(current_string->character_string + (current_string->size - 1), character_string, character_string_size);
+    hallocy_copy_memory(current_string->character_string + current_string->size, character_string, character_string_size);
 
     current_string->size += character_string_size;
     current_string->character_string[current_string->size] = '\0';
@@ -96,7 +95,7 @@ FledastyError fledasty_utf8_string_insert_at_index(FledastyUtf8String *current_s
         return FLEDASTY_ERROR_INVALID_POINTER;
     }
 
-    if (index >= current_string->size) {
+    if (index > current_string->size) {
         return FLEDASTY_ERROR_INDEX_OUT_OF_RANGE;
     }
 
@@ -113,6 +112,7 @@ FledastyError fledasty_utf8_string_insert_at_index(FledastyUtf8String *current_s
     hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
     
     current_string->size += character_string_size;
+    current_string->character_string[current_string->size] = '\0';
     return FLEDASTY_ERROR_NONE;
 }
 
@@ -127,23 +127,23 @@ FledastyError fledasty_utf8_string_insert_before_string(FledastyUtf8String *curr
 
     size_t index = 0;
     while (index < (current_string->size - before_character_string_size) && !hallocy_compare_memory(current_string->character_string + index, before_character_string, before_character_string_size)) {
+        if (hallocy_compare_memory(current_string->character_string + index, before_character_string, before_character_string_size)) {
+            if (current_string->capacity <= current_string->size + character_string_size) {
+                current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size + 1;
+                current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));
+            }
+        
+            hallocy_move_memory(current_string->character_string + (index + character_string_size), current_string->character_string + index, current_string->size - index);
+            hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
+            
+            current_string->size += character_string_size;
+            return FLEDASTY_ERROR_NONE;
+        }
+
         index += 1;
     }
 
-    if (index == current_string->size - before_character_string_size) {
-        return FLEDASTY_ERROR_VALUE_NOT_FOUND;
-    }
-
-    if (current_string->capacity <= current_string->size + character_string_size) {
-        current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size;
-        current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));
-    }
-
-    hallocy_move_memory(current_string->character_string + (index + character_string_size), current_string->character_string + index, current_string->size - index);
-    hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
-    
-    current_string->size += character_string_size;
-    return FLEDASTY_ERROR_NONE;
+    return FLEDASTY_ERROR_VALUE_NOT_FOUND;   
 }
 
 FledastyError fledasty_utf8_string_insert_after_string(FledastyUtf8String *current_string, unsigned char *after_character_string, const size_t after_character_string_size, unsigned char *character_string, const size_t character_string_size) {
@@ -156,25 +156,25 @@ FledastyError fledasty_utf8_string_insert_after_string(FledastyUtf8String *curre
     }
 
     size_t index = 0;
-    while (index < (current_string->size - after_character_string_size) && !hallocy_compare_memory(current_string->character_string + index, after_character_string, after_character_string_size)) {
+    while (index < (current_string->size - after_character_string_size)) {
+        if (hallocy_compare_memory(current_string->character_string + index, after_character_string, after_character_string_size)) {
+            if (current_string->capacity <= current_string->size + character_string_size) {
+                current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size + 1;
+                current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));
+            }
+        
+            index += after_character_string_size;
+            hallocy_move_memory(current_string->character_string + (index + character_string_size), current_string->character_string + index, current_string->size - index + 1);
+            hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
+            
+            current_string->size += character_string_size;
+            return FLEDASTY_ERROR_NONE;
+        }
+
         index += 1;
     }
 
-    if (index == current_string->size - after_character_string_size) {
-        return FLEDASTY_ERROR_VALUE_NOT_FOUND;
-    }
-
-    if (current_string->capacity <= current_string->size + character_string_size) {
-        current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size;
-        current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));
-    }
-
-    index += after_character_string_size;
-    hallocy_move_memory(current_string->character_string + (index + character_string_size), current_string->character_string + index, current_string->size - index);
-    hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
-    
-    current_string->size += character_string_size;
-    return FLEDASTY_ERROR_NONE;
+    return FLEDASTY_ERROR_VALUE_NOT_FOUND;
 }
 
 FledastyError fledasty_utf8_string_pop(FledastyUtf8String *current_string) {
@@ -192,7 +192,7 @@ FledastyError fledasty_utf8_string_pop(FledastyUtf8String *current_string) {
         current_string->size -= 1;
     }
 
-    current_string->character_string[current_string->size - 1] = '\0';
+    current_string->character_string[current_string->size] = '\0';
 
     return FLEDASTY_ERROR_NONE;
 }
@@ -207,18 +207,19 @@ FledastyError fledasty_utf8_string_remove(FledastyUtf8String *current_string, un
     }
 
     size_t index = 0;
-    while (index < (current_string->size - character_string_size) && !hallocy_compare_memory(current_string->character_string + index, character_string, character_string_size)) {
+    while (index < (current_string->size - character_string_size)) {
+        if (hallocy_compare_memory(current_string->character_string + index, character_string, character_string_size)) {
+            hallocy_move_memory(current_string->character_string + index, current_string->character_string + index + character_string_size, current_string->size - (index + character_string_size));
+        
+            current_string->size -= character_string_size;
+            current_string->character_string[current_string->size] = '\0';
+            return FLEDASTY_ERROR_NONE;
+        }
+
         index += 1;
     }
 
-    if (index == current_string->size - character_string_size) {
-        return FLEDASTY_ERROR_VALUE_NOT_FOUND;
-    }
-
-    hallocy_move_memory(current_string->character_string + index, current_string->character_string + index + character_string_size, current_string->size - (index + character_string_size));
-    current_string->size -= character_string_size;
-
-    return FLEDASTY_ERROR_NONE;
+    return FLEDASTY_ERROR_VALUE_NOT_FOUND;
 }
 
 FledastyError fledasty_utf8_string_remove_range(FledastyUtf8String *current_string, const size_t start_index, const size_t end_index) {
@@ -226,13 +227,14 @@ FledastyError fledasty_utf8_string_remove_range(FledastyUtf8String *current_stri
         return FLEDASTY_ERROR_INVALID_POINTER;
     }
 
-    if (start_index > end_index || end_index > current_string->size) {
+    if (start_index >= end_index || end_index >= current_string->size) {
         return FLEDASTY_ERROR_INDEX_OUT_OF_RANGE;
     }
 
     hallocy_move_memory(current_string->character_string + start_index, current_string->character_string + end_index, current_string->size - end_index);
-    current_string->size -= end_index - start_index;
 
+    current_string->size -= end_index - start_index;
+    current_string->character_string[current_string->size] = '\0';
     return FLEDASTY_ERROR_NONE;
 }
 
@@ -257,19 +259,25 @@ FledastyError fledasty_utf8_string_replace_string(FledastyUtf8String *current_st
     }
 
     size_t index = 0;
-    while (index < current_string->size - replace_character_string_size && !hallocy_compare_memory(current_string->character_string + index, replace_character_string, replace_character_string_size)) {
+    while (index < current_string->size - replace_character_string_size) {
+        if (hallocy_compare_memory(current_string->character_string + index, replace_character_string, replace_character_string_size)) {
+            const size_t new_size = current_string->size + (character_string_size - replace_character_string_size);
+            if (current_string->capacity <= new_size) {
+                current_string->capacity += (current_string->capacity > character_string_size) ? current_string->capacity : character_string_size;
+                current_string->character_string = (unsigned char*)hallocy_realloc(current_string->character_string, current_string->capacity * sizeof(unsigned char));
+            }
+
+            hallocy_move_memory(current_string->character_string + index + character_string_size, current_string->character_string + index + replace_character_string_size, current_string->size - (index + replace_character_string_size));
+            hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
+
+            current_string->size = new_size;
+            current_string->character_string[current_string->size] = '\0';
+            return FLEDASTY_ERROR_NONE;
+        }
         index += 1;
     }
 
-    if (index == current_string->size - replace_character_string_size) {
-        return FLEDASTY_ERROR_VALUE_NOT_FOUND;
-    }
-
-    hallocy_move_memory(current_string->character_string + index + character_string_size, current_string->character_string + index + replace_character_string_size, current_string->size - (index + replace_character_string_size));
-    hallocy_copy_memory(current_string->character_string + index, character_string, character_string_size);
-
-    current_string->size += character_string_size - replace_character_string_size;
-    return FLEDASTY_ERROR_NONE;
+    return FLEDASTY_ERROR_VALUE_NOT_FOUND;
 }
 
 bool fledasty_utf8_string_has_string(const FledastyUtf8String *current_string, unsigned char *character_string, const size_t character_string_size) {
@@ -345,7 +353,7 @@ FledastyUtf8String fledasty_utf8_string_encode(const uint32_t *unicode, const si
     }
 
     utf8_string.size = string_index;
-    if (utf8_string.capacity <= utf8_string.size + 1) {
+    if (utf8_string.capacity <= utf8_string.size) {
         utf8_string.capacity += utf8_string.capacity;
         utf8_string.character_string = (unsigned char*)hallocy_realloc(utf8_string.character_string, utf8_string.capacity);
     }
diff --git a/Tests/Main.c b/Tests/Main.c
index fab8be1..9ea11ef 100644
--- a/Tests/Main.c
+++ b/Tests/Main.c
@@ -237,7 +237,7 @@ int main() {
     fledasty_hash_table_destroy(&test_hash_table);
     FledastyUtf8String test_utf8_string;
     unsigned char *test_string = (unsigned char*)"😀€Testing";
-    fledasty_utf8_string_initialize(&test_utf8_string, test_string, 15);
+    fledasty_utf8_string_initialize(&test_utf8_string, test_string, 14);
     printf("%s\n", test_string);
     printf("%s\n", test_utf8_string.character_string);
 
@@ -247,7 +247,7 @@ int main() {
     printf("Insert Before: %s\n", test_utf8_string.character_string);
     fledasty_utf8_string_insert_after_string(&test_utf8_string, (unsigned char*)"😀", 4, (unsigned char*)"Bye", 3);
     printf("Insert After: %s\n", test_utf8_string.character_string);
-    fledasty_utf8_string_insert_at_index(&test_utf8_string, test_utf8_string.size - 1, (unsigned char*)"index", 5);
+    fledasty_utf8_string_insert_at_index(&test_utf8_string, test_utf8_string.size, (unsigned char*)"index", 5);
     printf("Insert at Index: %s\n", test_utf8_string.character_string);
     fledasty_utf8_string_replace_string(&test_utf8_string, (unsigned char*)"😀", 4, (unsigned char*)"𓃶 ", 5);
     printf("Replace: %s\n", test_utf8_string.character_string);
@@ -255,7 +255,7 @@ int main() {
     printf("Pop: %s\n", test_utf8_string.character_string);
     fledasty_utf8_string_remove(&test_utf8_string, (unsigned char*)"𓃶 ", 5);
     printf("Remove: %s\n", test_utf8_string.character_string);
-    fledasty_utf8_string_remove_range(&test_utf8_string, 0, 5);
+    fledasty_utf8_string_remove_range(&test_utf8_string, 0, 6);
     printf("Remove range: %s\n", test_utf8_string.character_string);
 
     if (fledasty_utf8_string_has_string(&test_utf8_string, (unsigned char*)"😀", 4)) {