diff --git a/backend/prepare.sql b/backend/prepare.sql
index 12821e0..2f9fce4 100644
--- a/backend/prepare.sql
+++ b/backend/prepare.sql
@@ -32,21 +32,14 @@ CREATE TABLE IF NOT EXISTS product_prices (
     FOREIGN KEY(product) REFERENCES products(id)
 );
 
-CREATE TABLE IF NOT EXISTS carts (
-    id INTEGER PRIMARY KEY,
-    user INTEGER NOT NULL,
-
-    FOREIGN KEY(user) REFERENCES users(id)
-);
-
 CREATE TABLE IF NOT EXISTS cart_items (
     id INTEGER PRIMARY KEY,
-    cart INTEGER NOT NULL,
+    user INTEGER NOT NULL,
     product INTEGER NOT NULL,
     amount INTEGER NOT NULL,
 
 
-    FOREIGN KEY(cart) REFERENCES carts(id),
+    FOREIGN KEY(user) REFERENCES users(id),
     FOREIGN KEY(product) REFERENCES product(id)
 );
 
diff --git a/backend/src/controllers/controllers.h b/backend/src/controllers/controllers.h
index 652301e..0716e55 100644
--- a/backend/src/controllers/controllers.h
+++ b/backend/src/controllers/controllers.h
@@ -68,7 +68,7 @@ const Session* middleware_session(HttpCtx* ctx);
 #define RESPOND_SERVER_ERROR(HTTP_CTX)                                         \
     RESPOND_JSON(HTTP_CTX, 500, "{\"ok\":false,\"msg\":\"server error\"}")
 
-__attribute__((unused)) static inline void ___include_user(void)
+__attribute__((unused)) static inline void ___controllers_include_user(void)
 {
     RESPOND((HttpCtx*)0, 200, "text/html", "")
 }
diff --git a/backend/src/db/db.h b/backend/src/db/db.h
index 2cc15cb..cadd373 100644
--- a/backend/src/db/db.h
+++ b/backend/src/db/db.h
@@ -30,4 +30,5 @@ DbRes db_user_with_email(Db* db, User* user, const char* email);
 /// Expects `vec` to be constructed.
 DbRes db_product_all(Db* db, ProductVec* vec);
 
-DbRes db_cart_items_with_user_id(Db* db, CartItemVec* vec, int64_t user_id);
+__attribute__((deprecated("store in memory instead"))) DbRes
+db_cart_items_with_user_id(Db* db, CartItemVec* vec, int64_t user_id);
diff --git a/backend/src/db/db_sqlite.c b/backend/src/db/db_sqlite.c
index 87f4ff1..41383c0 100644
--- a/backend/src/db/db_sqlite.c
+++ b/backend/src/db/db_sqlite.c
@@ -282,7 +282,6 @@ l0_return:
 
 DbRes db_cart_items_with_user_id(Db* db, CartItemVec* vec, int64_t user_id)
 {
-    static_assert(sizeof(Cart) == 16, "model has changed");
     static_assert(sizeof(CartItem) == 32, "model has changed");
 
     sqlite3* connection;
@@ -290,45 +289,19 @@ DbRes db_cart_items_with_user_id(Db* db, CartItemVec* vec, int64_t user_id)
     DbRes res;
 
     sqlite3_stmt* stmt;
-    int sqlite_res = sqlite3_prepare_v2(connection,
-        "SELECT id "
-        " FROM carts WHERE user = ?",
-        -1,
-        &stmt,
-        NULL);
-    if (sqlite_res != SQLITE_OK) {
-        fprintf(stderr,
-            "error: %s\n  at %s:%d\n",
-            sqlite3_errmsg(connection),
-            __func__,
-            __LINE__);
-        res = DbRes_Error;
-        goto l0_return;
-    }
-    sqlite3_bind_int64(stmt, 1, user_id);
-
-    int step_res = sqlite3_step(stmt);
-    if (step_res == SQLITE_DONE) {
-        res = DbRes_NotFound;
-        goto l0_return;
-    } else if (step_res != SQLITE_ROW) {
-        fprintf(stderr, "error: %s\n", sqlite3_errmsg(connection));
-        res = DbRes_Error;
-        goto l0_return;
-    }
-    int64_t cart_id = GET_INT(0);
+    int sqlite_res;
 
     sqlite_res = sqlite3_prepare_v2(connection,
-        "SELECT id, cart, product, amount FROM cart_items WHERE cart = ?",
+        "SELECT id, user, product, amount FROM cart_items WHERE user = ?",
         -1,
         &stmt,
         NULL);
-    sqlite3_bind_int64(stmt, 1, cart_id);
+    sqlite3_bind_int64(stmt, 1, user_id);
 
     while ((sqlite_res = sqlite3_step(stmt)) == SQLITE_ROW) {
         CartItem cart_item = {
             .id = GET_INT(0),
-            .cart_id = GET_INT(1),
+            .user_id = GET_INT(1),
             .product_id = GET_INT(2),
             .amount = GET_INT(3),
         };
diff --git a/backend/src/main.c b/backend/src/main.c
index 7c5619a..7a7771a 100644
--- a/backend/src/main.c
+++ b/backend/src/main.c
@@ -1,3 +1,4 @@
+#include "collections/kv_map.h"
 #include "controllers/controllers.h"
 #include "db/db_sqlite.h"
 #include "http/http.h"
@@ -61,9 +62,13 @@ int main(void)
     db_sqlite_free(db);
 }
 
+#ifdef RUN_TESTS
 void test(void)
 {
-    str_util_test();
-    printf("ALL TESTS PASSED 💅\n");
+    test_util_str();
+    test_collections_kv_map();
+    printf("\n\x1b[1;97m ALL TESTS \x1b[1;92mPASSED"
+           " \x1b[1;97mSUCCESSFULLY 💅\x1b[0m\n\n");
     exit(0);
 }
+#endif
diff --git a/backend/src/models/models.c b/backend/src/models/models.c
index 43e1c53..93b4c8a 100644
--- a/backend/src/models/models.c
+++ b/backend/src/models/models.c
@@ -38,13 +38,6 @@ void product_price_destroy(ProductPrice* m)
     (void)m;
 }
 
-void cart_destroy(Cart* m)
-{
-    static_assert(sizeof(Cart) == 16, "model has changed");
-
-    (void)m;
-}
-
 void cart_item_destroy(CartItem* m)
 {
     static_assert(sizeof(CartItem) == 32, "model has changed");
@@ -163,25 +156,6 @@ char* product_price_to_json_string(const ProductPrice* m)
     return result;
 }
 
-char* cart_to_json_string(const Cart* m)
-{
-    static_assert(sizeof(Cart) == 16, "model has changed");
-
-    String string;
-    string_construct(&string);
-    string_pushf(&string,
-        "{"
-        "\"id\":%ld,"
-        "\"user_id\":%ld"
-        "}",
-        m->id,
-        m->user_id);
-
-    char* result = string_copy(&string);
-    string_destroy(&string);
-    return result;
-}
-
 char* cart_item_to_json_string(const CartItem* m)
 {
     static_assert(sizeof(CartItem) == 32, "model has changed");
@@ -191,12 +165,12 @@ char* cart_item_to_json_string(const CartItem* m)
     string_pushf(&string,
         "{"
         "\"id\":%ld,"
-        "\"cart_id\":%ld,"
+        "\"user_id\":%ld,"
         "\"product_id\":%ld,"
         "\"amount\":%ld"
         "}",
         m->id,
-        m->cart_id,
+        m->user_id,
         m->product_id,
         m->amount);
 
@@ -356,30 +330,13 @@ int product_price_from_json(ProductPrice* m, const JsonValue* json)
     return 0;
 }
 
-int cart_from_json(Cart* m, const JsonValue* json)
-{
-    static_assert(sizeof(Cart) == 16, "model has changed");
-
-    ObjField fields[] = {
-        { "id", JsonType_Number },
-        { "user_id", JsonType_Number },
-    };
-    if (!obj_conforms(json, fields, sizeof(fields) / sizeof(fields[0])))
-        return -1;
-    *m = (Cart) {
-        .id = GET_INT("id"),
-        .user_id = GET_INT("user_id"),
-    };
-    return 0;
-}
-
 int cart_item_from_json(CartItem* m, const JsonValue* json)
 {
     static_assert(sizeof(CartItem) == 32, "model has changed");
 
     ObjField fields[] = {
         { "id", JsonType_Number },
-        { "cart_id", JsonType_Number },
+        { "user_id", JsonType_Number },
         { "product_id", JsonType_Number },
         { "amount", JsonType_Number },
     };
@@ -387,7 +344,7 @@ int cart_item_from_json(CartItem* m, const JsonValue* json)
         return -1;
     *m = (CartItem) {
         .id = GET_INT("id"),
-        .cart_id = GET_INT("cart_id"),
+        .user_id = GET_INT("user_id"),
         .product_id = GET_INT("product_id"),
         .amount = GET_INT("amount"),
     };
diff --git a/backend/src/models/models.h b/backend/src/models/models.h
index d62b979..219a0ce 100644
--- a/backend/src/models/models.h
+++ b/backend/src/models/models.h
@@ -34,11 +34,6 @@ typedef struct {
 typedef struct {
     int64_t id;
     int64_t user_id;
-} Cart;
-
-typedef struct {
-    int64_t id;
-    int64_t cart_id;
     int64_t product_id;
     int64_t amount;
 } CartItem;
@@ -47,7 +42,6 @@ void user_destroy(User* model);
 void coord_destroy(Coord* model);
 void product_destroy(Product* model);
 void product_price_destroy(ProductPrice* model);
-void cart_destroy(Cart* model);
 void cart_item_destroy(CartItem* model);
 
 //
diff --git a/backend/src/models/models_json.h b/backend/src/models/models_json.h
index 256d56f..7c63df1 100644
--- a/backend/src/models/models_json.h
+++ b/backend/src/models/models_json.h
@@ -9,7 +9,6 @@ DEFINE_MODEL_JSON(User, user)
 DEFINE_MODEL_JSON(Coord, coord)
 DEFINE_MODEL_JSON(Product, product)
 DEFINE_MODEL_JSON(ProductPrice, product_price)
-DEFINE_MODEL_JSON(Cart, cart)
 DEFINE_MODEL_JSON(CartItem, cart_item)
 
 DEFINE_MODEL_JSON(UsersRegisterReq, users_register_req)
diff --git a/backend/src/util/panic.h b/backend/src/util/panic.h
index e6d26e7..b300ef4 100644
--- a/backend/src/util/panic.h
+++ b/backend/src/util/panic.h
@@ -4,12 +4,18 @@
 #include <stdlib.h>
 
 #define PANIC(...)                                                             \
-    (fputs("\x1b[1;31mpanic\x1b[97m: ", stderr), fprintf(stderr, __VA_ARGS__), \
-        fprintf(stderr, "\x1b[0m\n\tin %s:%d\n\tat %s:%d\n", __func__,         \
-            __LINE__, __FILE__, __LINE__),                                     \
-        exit(1), (void)0)
+    (fputs("\x1b[1;31mpanic\x1b[97m: ", stderr),                               \
+        fprintf(stderr, __VA_ARGS__),                                          \
+        fprintf(stderr,                                                        \
+            "\x1b[0m\n\tin %s:%d\n\tat %s:%d\n",                               \
+            __func__,                                                          \
+            __LINE__,                                                          \
+            __FILE__,                                                          \
+            __LINE__),                                                         \
+        exit(1),                                                               \
+        (void)0)
 
-__attribute__((unused)) static inline void ___include_user(void)
+__attribute__((unused)) static inline void ___panic_h_include_user(void)
 {
     PANIC("");
 }
diff --git a/backend/src/util/str.c b/backend/src/util/str.c
index 02d9161..b8054e5 100644
--- a/backend/src/util/str.c
+++ b/backend/src/util/str.c
@@ -260,7 +260,8 @@ char* str_random(size_t length)
     return string;
 }
 
-void str_util_test(void)
+#ifdef RUN_TESTS
+void test_util_str(void)
 {
     {
         char* hash = str_hash("1234");
@@ -282,3 +283,4 @@ void str_util_test(void)
         free(token_2);
     }
 }
+#endif
diff --git a/backend/src/util/str.h b/backend/src/util/str.h
index 5ccf646..ae26315 100644
--- a/backend/src/util/str.h
+++ b/backend/src/util/str.h
@@ -42,4 +42,6 @@ uint64_t str_fast_hash(const char* input);
 
 char* str_random(size_t length);
 
-void str_util_test(void);
+#ifdef RUN_TESTS
+void test_util_str(void);
+#endif