diff --git a/src/app/account/page.tsx b/src/app/account/page.tsx
index 4e98014..0023029 100644
--- a/src/app/account/page.tsx
+++ b/src/app/account/page.tsx
@@ -7,7 +7,7 @@ import { Label } from '@/components/ui/label';
 import { Input } from '@/components/ui/input';
 import { URL_SIGN_IN } from '@/lib/constants';
 import generateSampleData from '@/lib/actions/generateSampleData';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { ServerActionTrigger } from '@/components/form/serverActionTrigger';
 import accountDelete from '@/lib/actions/accountDelete';
 
@@ -20,21 +20,21 @@ export default async function AccountPage() {
     }
 
     let paymentCount = 0;
-    paymentCount = await prismaClient.payment.count({
+    paymentCount = await prisma.payment.count({
         where: {
             userId: user.id,
         },
     });
 
     let entityCount = 0;
-    entityCount = await prismaClient.entity.count({
+    entityCount = await prisma.entity.count({
         where: {
             userId: user.id,
         },
     });
 
     let categoryCount = 0;
-    categoryCount = await prismaClient.category.count({
+    categoryCount = await prisma.category.count({
         where: {
             userId: user.id,
         },
diff --git a/src/app/categories/page.tsx b/src/app/categories/page.tsx
index f7bee73..73c6251 100644
--- a/src/app/categories/page.tsx
+++ b/src/app/categories/page.tsx
@@ -1,5 +1,5 @@
 import { getUser } from '@/auth';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import React from 'react';
 import CategoryPageClientContent from '@/components/categoryPageClientComponents';
 import categoryCreateUpdate from '@/lib/actions/categoryCreateUpdate';
@@ -9,7 +9,7 @@ export default async function CategoriesPage() {
 
     const user = await getUser();
 
-    const categories = await prismaClient.category.findMany({
+    const categories = await prisma.category.findMany({
         where: {
             userId: user?.id,
         },
diff --git a/src/app/entities/page.tsx b/src/app/entities/page.tsx
index f5b7d0a..e39176c 100644
--- a/src/app/entities/page.tsx
+++ b/src/app/entities/page.tsx
@@ -1,4 +1,4 @@
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { getUser } from '@/auth';
 import React from 'react';
 import EntityPageClientContent from '@/components/entityPageClientComponents';
@@ -9,7 +9,7 @@ export default async function EntitiesPage() {
 
     const user = await getUser();
 
-    const entities = await prismaClient.entity.findMany({
+    const entities = await prisma.entity.findMany({
         where: {
             userId: user?.id,
         },
@@ -23,7 +23,7 @@ export default async function EntitiesPage() {
         ],
     });
 
-    const categories = await prismaClient.category.findMany({
+    const categories = await prisma.category.findMany({
         where: {
             userId: user?.id,
         },
diff --git a/src/app/page.tsx b/src/app/page.tsx
index 54450d0..72c34da 100644
--- a/src/app/page.tsx
+++ b/src/app/page.tsx
@@ -1,7 +1,7 @@
 import React from 'react';
 import { Category, Entity, EntityType } from '@prisma/client';
 import { Scope, ScopeType } from '@/lib/types/scope';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { getUser } from '@/auth';
 import DashboardPageClient from '@/components/dashboardPageClientComponents';
 
@@ -25,7 +25,7 @@ export default async function DashboardPage(props: { searchParams?: { scope: Sco
     const scope = Scope.of(props.searchParams?.scope || ScopeType.ThisMonth);
 
     // get all payments in the current scope
-    const payments = await prismaClient.payment.findMany({
+    const payments = await prisma.payment.findMany({
         where: {
             userId: user?.id,
             date: {
@@ -108,6 +108,7 @@ export default async function DashboardPage(props: { searchParams?: { scope: Sco
             userId: '',
             name: 'Other',
             type: EntityType.Entity,
+            defaultCategoryId: null,
             createdAt: new Date(),
             updatedAt: new Date(),
         },
diff --git a/src/app/payments/page.tsx b/src/app/payments/page.tsx
index bbec906..f1ffa66 100644
--- a/src/app/payments/page.tsx
+++ b/src/app/payments/page.tsx
@@ -1,5 +1,5 @@
 import { getUser } from '@/auth';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import React from 'react';
 import PaymentPageClientContent from '@/components/paymentPageClientComponents';
 import paymentCreateUpdate from '@/lib/actions/paymentCreateUpdate';
@@ -9,7 +9,7 @@ export default async function PaymentsPage() {
 
     const user = await getUser();
 
-    const payments = await prismaClient.payment.findMany({
+    const payments = await prisma.payment.findMany({
         where: {
             userId: user?.id,
         },
@@ -23,7 +23,7 @@ export default async function PaymentsPage() {
         ],
     });
 
-    const entities = await prismaClient.entity.findMany({
+    const entities = await prisma.entity.findMany({
         where: {
             userId: user?.id,
         },
@@ -37,7 +37,7 @@ export default async function PaymentsPage() {
         ],
     });
 
-    const categories = await prismaClient.category.findMany({
+    const categories = await prisma.category.findMany({
         where: {
             userId: user?.id,
         },
diff --git a/src/auth.ts b/src/auth.ts
index 26cdb6c..ae752a6 100644
--- a/src/auth.ts
+++ b/src/auth.ts
@@ -1,9 +1,9 @@
 import { Lucia } from 'lucia';
 import { PrismaAdapter } from '@lucia-auth/adapter-prisma';
 import { cookies } from 'next/headers';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 
-const adapter = new PrismaAdapter(prismaClient.session, prismaClient.user);
+const adapter = new PrismaAdapter(prisma.session, prisma.user);
 
 export const lucia = new Lucia(adapter, {
     sessionCookie: {
diff --git a/src/lib/actions/accountDelete.ts b/src/lib/actions/accountDelete.ts
index 28cf745..952e31c 100644
--- a/src/lib/actions/accountDelete.ts
+++ b/src/lib/actions/accountDelete.ts
@@ -1,7 +1,7 @@
 import { ActionResponse } from '@/lib/types/actionResponse';
 import { URL_SIGN_IN } from '@/lib/constants';
 import { getUser, lucia } from '@/auth';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { cookies } from 'next/headers';
 
 export default async function accountDelete(): Promise<ActionResponse> {
@@ -17,31 +17,31 @@ export default async function accountDelete(): Promise<ActionResponse> {
         };
     }
 
-    await prismaClient.payment.deleteMany({
+    await prisma.payment.deleteMany({
         where: {
             userId: user.id,
         },
     });
 
-    await prismaClient.entity.deleteMany({
+    await prisma.entity.deleteMany({
         where: {
             userId: user.id,
         },
     });
 
-    await prismaClient.category.deleteMany({
+    await prisma.category.deleteMany({
         where: {
             userId: user.id,
         },
     });
 
-    await prismaClient.session.deleteMany({
+    await prisma.session.deleteMany({
         where: {
             userId: user.id,
         },
     });
 
-    await prismaClient.user.delete({
+    await prisma.user.delete({
         where: {
             id: user.id,
         },
diff --git a/src/lib/actions/categoryCreateUpdate.ts b/src/lib/actions/categoryCreateUpdate.ts
index a7796d5..11bdd5f 100644
--- a/src/lib/actions/categoryCreateUpdate.ts
+++ b/src/lib/actions/categoryCreateUpdate.ts
@@ -1,6 +1,6 @@
 import { z } from 'zod';
 import { ActionResponse } from '@/lib/types/actionResponse';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { getUser } from '@/auth';
 import { URL_SIGN_IN } from '@/lib/constants';
 import { categoryFormSchema } from '@/lib/form-schemas/categoryFormSchema';
@@ -25,7 +25,7 @@ export default async function categoryCreateUpdate({
     // create/update category
     try {
         if (id) {
-            await prismaClient.category.update({
+            await prisma.category.update({
                     where: {
                         id: id,
                     },
@@ -42,7 +42,7 @@ export default async function categoryCreateUpdate({
                 message: `'${name}' updated`,
             };
         } else {
-            await prismaClient.category.create({
+            await prisma.category.create({
                 data: {
                     userId: user.id,
                     name: name,
diff --git a/src/lib/actions/categoryDelete.ts b/src/lib/actions/categoryDelete.ts
index 11cc496..8773fe3 100644
--- a/src/lib/actions/categoryDelete.ts
+++ b/src/lib/actions/categoryDelete.ts
@@ -1,5 +1,5 @@
 import { ActionResponse } from '@/lib/types/actionResponse';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { getUser } from '@/auth';
 import { URL_SIGN_IN } from '@/lib/constants';
 
@@ -25,7 +25,7 @@ export default async function categoryDelete(id: number): Promise<ActionResponse
     }
 
     // check that category is associated with user
-    const category = await prismaClient.category.findFirst({
+    const category = await prisma.category.findFirst({
         where: {
             id: id,
             userId: user.id,
@@ -40,7 +40,7 @@ export default async function categoryDelete(id: number): Promise<ActionResponse
 
     // delete category
     try {
-        await prismaClient.category.delete({
+        await prisma.category.delete({
                 where: {
                     id: category.id,
                     userId: user.id,
diff --git a/src/lib/actions/entityCreateUpdate.ts b/src/lib/actions/entityCreateUpdate.ts
index a1d4101..465c567 100644
--- a/src/lib/actions/entityCreateUpdate.ts
+++ b/src/lib/actions/entityCreateUpdate.ts
@@ -1,7 +1,7 @@
 import { z } from 'zod';
 import { ActionResponse } from '@/lib/types/actionResponse';
 import { entityFormSchema } from '@/lib/form-schemas/entityFormSchema';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { getUser } from '@/auth';
 import { URL_SIGN_IN } from '@/lib/constants';
 
@@ -26,7 +26,7 @@ export default async function entityCreateUpdate({
     // create/update entity
     try {
         if (id) {
-            await prismaClient.entity.update({
+            await prisma.entity.update({
                     where: {
                         id: id,
                     },
@@ -44,7 +44,7 @@ export default async function entityCreateUpdate({
                 message: `${type} '${name}' updated`,
             };
         } else {
-            await prismaClient.entity.create({
+            await prisma.entity.create({
                 data: {
                     userId: user.id,
                     name: name,
diff --git a/src/lib/actions/entityDelete.ts b/src/lib/actions/entityDelete.ts
index cb2dd45..2e0e3eb 100644
--- a/src/lib/actions/entityDelete.ts
+++ b/src/lib/actions/entityDelete.ts
@@ -1,5 +1,5 @@
 import { ActionResponse } from '@/lib/types/actionResponse';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { getUser } from '@/auth';
 import { URL_SIGN_IN } from '@/lib/constants';
 
@@ -25,7 +25,7 @@ export default async function entityDelete(id: number): Promise<ActionResponse>
     }
 
     // check that entity is associated with user
-    const entity = await prismaClient.entity.findFirst({
+    const entity = await prisma.entity.findFirst({
         where: {
             id: id,
             userId: user.id,
@@ -40,7 +40,7 @@ export default async function entityDelete(id: number): Promise<ActionResponse>
 
     // delete entity
     try {
-        await prismaClient.entity.delete({
+        await prisma.entity.delete({
                 where: {
                     id: entity.id,
                     userId: user.id,
diff --git a/src/lib/actions/generateSampleData.ts b/src/lib/actions/generateSampleData.ts
index 86db509..09ea36b 100644
--- a/src/lib/actions/generateSampleData.ts
+++ b/src/lib/actions/generateSampleData.ts
@@ -1,4 +1,4 @@
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import type { Category, Entity } from '@prisma/client';
 import { EntityType } from '@prisma/client';
 import { getUser } from '@/auth';
@@ -19,12 +19,12 @@ export default async function generateSampleData(): Promise<ActionResponse> {
     }
 
     // Categories: create sample data
-    const categories: Category[] = await prismaClient.category.findMany({where: {userId: user.id}});
-    if (await prismaClient.category.count({where: {userId: user.id}}) == 0) {
+    const categories: Category[] = await prisma.category.findMany({where: {userId: user.id}});
+    if (await prisma.category.count({where: {userId: user.id}}) == 0) {
 
         console.log('Creating sample categories...');
 
-        categories.push(await prismaClient.category.create({
+        categories.push(await prisma.category.create({
             data: {
                 userId: user.id,
                 name: 'Groceries',
@@ -32,7 +32,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
             },
         }));
 
-        categories.push(await prismaClient.category.create({
+        categories.push(await prisma.category.create({
             data: {
                 userId: user.id,
                 name: 'Drugstore items',
@@ -40,7 +40,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
             },
         }));
 
-        categories.push(await prismaClient.category.create({
+        categories.push(await prisma.category.create({
             data: {
                 userId: user.id,
                 name: 'Going out',
@@ -48,7 +48,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
             },
         }));
 
-        categories.push(await prismaClient.category.create({
+        categories.push(await prisma.category.create({
             data: {
                 userId: user.id,
                 name: 'Random stuff',
@@ -56,7 +56,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
             },
         }));
 
-        categories.push(await prismaClient.category.create({
+        categories.push(await prisma.category.create({
             data: {
                 userId: user.id,
                 name: 'Salary',
@@ -69,12 +69,12 @@ export default async function generateSampleData(): Promise<ActionResponse> {
     console.log(categories);
 
     // Entities: create sample data
-    const entities: Entity[] = await prismaClient.entity.findMany({where: {userId: user.id}});
-    if (await prismaClient.entity.count({where: {userId: user.id}}) == 0) {
+    const entities: Entity[] = await prisma.entity.findMany({where: {userId: user.id}});
+    if (await prisma.entity.count({where: {userId: user.id}}) == 0) {
 
         console.log('Creating sample entities...');
 
-        entities.push(await prismaClient.entity.create({
+        entities.push(await prisma.entity.create({
             data: {
                 userId: user.id,
                 name: 'Main Account',
@@ -82,7 +82,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
             },
         }));
 
-        entities.push(await prismaClient.entity.create({
+        entities.push(await prisma.entity.create({
             data: {
                 userId: user.id,
                 name: 'Company',
@@ -90,7 +90,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
             },
         }));
 
-        entities.push(await prismaClient.entity.create({
+        entities.push(await prisma.entity.create({
             data: {
                 userId: user.id,
                 name: 'Supermarket 1',
@@ -98,7 +98,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
             },
         }));
 
-        entities.push(await prismaClient.entity.create({
+        entities.push(await prisma.entity.create({
             data: {
                 userId: user.id,
                 name: 'Supermarket 2',
@@ -106,7 +106,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
             },
         }));
 
-        entities.push(await prismaClient.entity.create({
+        entities.push(await prisma.entity.create({
             data: {
                 userId: user.id,
                 name: 'Supermarket 3',
@@ -114,7 +114,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
             },
         }));
 
-        entities.push(await prismaClient.entity.create({
+        entities.push(await prisma.entity.create({
             data: {
                 userId: user.id,
                 name: 'Supermarket 4',
@@ -129,14 +129,14 @@ export default async function generateSampleData(): Promise<ActionResponse> {
     // Payments: create sample data
     console.log('Creating sample payments...');
 
-    if (await prismaClient.payment.count({where: {userId: user.id}}) == 0) {
+    if (await prisma.payment.count({where: {userId: user.id}}) == 0) {
         for (let i = 0; i < 4; i++) {
 
             const date = new Date();
             date.setDate(1);
             date.setMonth(date.getMonth() - i);
 
-            await prismaClient.payment.create({
+            await prisma.payment.create({
                 data: {
                     userId: user.id,
                     amount: 200000,
@@ -164,7 +164,7 @@ export default async function generateSampleData(): Promise<ActionResponse> {
         const date = new Date(
             new Date().getTime() - Math.floor(Math.random() * 10000000000));
 
-        await prismaClient.payment.create({
+        await prisma.payment.create({
             data: {
                 userId: user.id,
                 amount: Math.floor(
diff --git a/src/lib/actions/paymentCreateUpdate.ts b/src/lib/actions/paymentCreateUpdate.ts
index a321062..4a66d33 100644
--- a/src/lib/actions/paymentCreateUpdate.ts
+++ b/src/lib/actions/paymentCreateUpdate.ts
@@ -1,6 +1,6 @@
 import { z } from 'zod';
 import { ActionResponse } from '@/lib/types/actionResponse';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { getUser } from '@/auth';
 import { URL_SIGN_IN } from '@/lib/constants';
 import { paymentFormSchema } from '@/lib/form-schemas/paymentFormSchema';
@@ -29,7 +29,7 @@ export default async function paymentCreateUpdate({
     // create/update payment
     try {
         if (id) {
-            await prismaClient.payment.update({
+            await prisma.payment.update({
                     where: {
                         id: id,
                     },
@@ -50,7 +50,7 @@ export default async function paymentCreateUpdate({
                 message: `Payment updated`,
             };
         } else {
-            await prismaClient.payment.create({
+            await prisma.payment.create({
                 data: {
                     userId: user.id,
                     amount: amount,
diff --git a/src/lib/actions/paymentDelete.ts b/src/lib/actions/paymentDelete.ts
index 3401e92..a3bfd16 100644
--- a/src/lib/actions/paymentDelete.ts
+++ b/src/lib/actions/paymentDelete.ts
@@ -1,5 +1,5 @@
 import { ActionResponse } from '@/lib/types/actionResponse';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 import { getUser } from '@/auth';
 import { URL_SIGN_IN } from '@/lib/constants';
 
@@ -25,7 +25,7 @@ export default async function paymentDelete(id: number): Promise<ActionResponse>
     }
 
     // check that payment is associated with user
-    const payment = await prismaClient.payment.findFirst({
+    const payment = await prisma.payment.findFirst({
         where: {
             id: id,
             userId: user.id,
@@ -40,7 +40,7 @@ export default async function paymentDelete(id: number): Promise<ActionResponse>
 
     // delete payment
     try {
-        await prismaClient.payment.delete({
+        await prisma.payment.delete({
                 where: {
                     id: payment.id,
                     userId: user.id,
diff --git a/src/lib/actions/signIn.ts b/src/lib/actions/signIn.ts
index 5168179..0e34e3d 100644
--- a/src/lib/actions/signIn.ts
+++ b/src/lib/actions/signIn.ts
@@ -5,12 +5,12 @@ import { cookies } from 'next/headers';
 import { signInFormSchema } from '@/lib/form-schemas/signInFormSchema';
 import { ActionResponse } from '@/lib/types/actionResponse';
 import { URL_HOME } from '@/lib/constants';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 
 export default async function signIn({username, password}: z.infer<typeof signInFormSchema>): Promise<ActionResponse> {
     'use server';
 
-    const existingUser = await prismaClient.user.findFirst({
+    const existingUser = await prisma.user.findFirst({
         where: {
             username: username.toLowerCase(),
         },
diff --git a/src/lib/actions/signUp.ts b/src/lib/actions/signUp.ts
index 1b40aff..d7ea888 100644
--- a/src/lib/actions/signUp.ts
+++ b/src/lib/actions/signUp.ts
@@ -6,7 +6,7 @@ import { cookies } from 'next/headers';
 import { signUpFormSchema } from '@/lib/form-schemas/signUpFormSchema';
 import { ActionResponse } from '@/lib/types/actionResponse';
 import { URL_HOME } from '@/lib/constants';
-import { prismaClient } from '@/prisma';
+import prisma from '@/prisma';
 
 export default async function signUp({username, password}: z.infer<typeof signUpFormSchema>): Promise<ActionResponse> {
     'use server';
@@ -14,7 +14,7 @@ export default async function signUp({username, password}: z.infer<typeof signUp
     const hashedPassword = await new Argon2id().hash(password);
     const userId = generateId(15);
 
-    const existingUser = await prismaClient.user.findFirst({
+    const existingUser = await prisma.user.findFirst({
         where: {
             username: username.toLowerCase(),
         },
@@ -27,7 +27,7 @@ export default async function signUp({username, password}: z.infer<typeof signUp
         };
     }
 
-    await prismaClient.user.create({
+    await prisma.user.create({
         data: {
             id: userId,
             username: username,
diff --git a/src/prisma.ts b/src/prisma.ts
index 5e41d6f..be21813 100644
--- a/src/prisma.ts
+++ b/src/prisma.ts
@@ -1,3 +1,18 @@
 import { PrismaClient } from '@prisma/client';
 
-export const prismaClient = new PrismaClient();
+const prismaClientSingleton = () => {
+    return new PrismaClient();
+};
+
+declare global {
+    // noinspection ES6ConvertVarToLetConst
+    var prismaGlobal: undefined | ReturnType<typeof prismaClientSingleton>;
+}
+
+const prisma = globalThis.prismaGlobal ?? prismaClientSingleton();
+
+export default prisma;
+
+if (process.env.NODE_ENV !== 'production') {
+    globalThis.prismaGlobal = prisma
+}