diff --git a/src/common/utils/constants.ts b/src/common/utils/constants.ts
index 9c68651..c7f2f1b 100644
--- a/src/common/utils/constants.ts
+++ b/src/common/utils/constants.ts
@@ -1,3 +1,5 @@
+import type { ZodString } from "zod";
+
 export const DEFAULT_PAGE = 1;
 export const DEFAULT_LIMIT = 10;
 export const MAX_LIMIT = 100;
@@ -8,5 +10,7 @@ export const AUTHORIZATION_ERROR_MESSAGE
 export const FORBIDDEN_ERROR_MESSAGE
   = "You are not allowed to perform this action.";
 export const INTERNAL_SERVER_ERROR_MESSAGE
-  = "Something went wrong, please try again later";
+  = "Something went wrong, please try again later.";
 export const VALIDATION_ERROR_MESSAGE = "The validation error(s)";
+export const NOT_AUTHORIZED = "User is not authorized";
+export const RESOURCE_NOT_FOUND = (resourceName: string, resourceId: ZodString) => `${resourceName} with id ${resourceId} does not exist`;
diff --git a/src/modules/activities/activity.handlers.ts b/src/modules/activities/activity.handlers.ts
index dca794b..874e4d2 100644
--- a/src/modules/activities/activity.handlers.ts
+++ b/src/modules/activities/activity.handlers.ts
@@ -1,6 +1,7 @@
 import { AuthRoles } from "@/common/enums";
 import { generateMetadata } from "@/common/helpers/metadata.helper";
 import type { AppRouteHandler } from "@/common/lib/types";
+import { AUTHORIZATION_ERROR_MESSAGE } from "@/common/utils/constants";
 import * as HTTPStatusCodes from "@/common/utils/http-status-codes.util";
 
 import { getActivitiesRepository } from "./activity.repository";
@@ -19,7 +20,7 @@ export const getActivities: AppRouteHandler<TGetActivitiesRoute> = async (
     return c.json(
       {
         success: false,
-        message: "You are not authorized, please login",
+        message: AUTHORIZATION_ERROR_MESSAGE,
       },
       HTTPStatusCodes.UNAUTHORIZED,
     );
diff --git a/src/modules/activities/activity.routes.ts b/src/modules/activities/activity.routes.ts
index f28ef93..eea08b3 100644
--- a/src/modules/activities/activity.routes.ts
+++ b/src/modules/activities/activity.routes.ts
@@ -8,6 +8,7 @@ import {
 } from "@/common/middlewares/auth.middleware";
 import createErrorSchema from "@/common/schema/create-error.schema";
 import { metadataSchema } from "@/common/schema/metadata.schema";
+import { AUTHORIZATION_ERROR_MESSAGE, VALIDATION_ERROR_MESSAGE } from "@/common/utils/constants";
 import * as HTTPStatusCodes from "@/common/utils/http-status-codes.util";
 
 import { activityQuerySchema } from "./activity.schema";
@@ -42,11 +43,11 @@ export const getActivitiesRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "You are not authorized, please login",
+      AUTHORIZATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.UNPROCESSABLE_ENTITY]: jsonContent(
       createErrorSchema(activityQuerySchema),
-      "The validation error(s)",
+      VALIDATION_ERROR_MESSAGE,
     ),
   },
 });
diff --git a/src/modules/auth/auth.handlers.ts b/src/modules/auth/auth.handlers.ts
index af8245b..a20cf0a 100644
--- a/src/modules/auth/auth.handlers.ts
+++ b/src/modules/auth/auth.handlers.ts
@@ -2,6 +2,7 @@ import { deleteCookie, setCookie } from "hono/cookie";
 
 import { AuthRoles } from "@/common/enums";
 import type { AppRouteHandler } from "@/common/lib/types";
+import { AUTHORIZATION_ERROR_MESSAGE } from "@/common/utils/constants";
 import {
   hashPassword,
   verifyPasswordHash,
@@ -199,7 +200,7 @@ export const logout: AppRouteHandler<TLogoutRoute> = async (c) => {
     return c.json(
       {
         success: false,
-        message: "You are not authorized, please login",
+        message: AUTHORIZATION_ERROR_MESSAGE,
       },
       HTTPStatusCodes.UNAUTHORIZED,
     );
@@ -233,7 +234,7 @@ export const loggedInUserDetails: AppRouteHandler<
     return c.json(
       {
         success: false,
-        message: "You are not authorized, please login",
+        message: AUTHORIZATION_ERROR_MESSAGE,
       },
       HTTPStatusCodes.UNAUTHORIZED,
     );
@@ -247,7 +248,7 @@ export const loggedInUserDetails: AppRouteHandler<
     return c.json(
       {
         success: false,
-        message: "You are not authorized, please login",
+        message: AUTHORIZATION_ERROR_MESSAGE,
       },
       HTTPStatusCodes.UNAUTHORIZED,
     );
diff --git a/src/modules/auth/auth.routes.ts b/src/modules/auth/auth.routes.ts
index 939d1d2..7afba2c 100644
--- a/src/modules/auth/auth.routes.ts
+++ b/src/modules/auth/auth.routes.ts
@@ -7,6 +7,7 @@ import {
   requireAuth,
 } from "@/common/middlewares/auth.middleware";
 import createErrorSchema from "@/common/schema/create-error.schema";
+import { AUTHORIZATION_ERROR_MESSAGE, INTERNAL_SERVER_ERROR_MESSAGE, VALIDATION_ERROR_MESSAGE } from "@/common/utils/constants";
 import * as HTTPStatusCodes from "@/common/utils/http-status-codes.util";
 import { insertUserSchema, selectUserSchema } from "@/db/schemas/user.model";
 
@@ -48,7 +49,7 @@ export const registerRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "The validation error(s)",
+      VALIDATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.CONFLICT]: jsonContent(
       z.object({
@@ -63,14 +64,14 @@ export const registerRoute = createRoute({
           password: z.string().min(8).max(60),
         }),
       ),
-      "The validation error(s)",
+      VALIDATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.INTERNAL_SERVER_ERROR]: jsonContent(
       z.object({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "Server side error(s)",
+      INTERNAL_SERVER_ERROR_MESSAGE,
     ),
   },
 });
@@ -112,14 +113,14 @@ export const loginRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "The validation error(s)",
+      VALIDATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.INTERNAL_SERVER_ERROR]: jsonContent(
       z.object({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "Server side error(s)",
+      INTERNAL_SERVER_ERROR_MESSAGE,
     ),
   },
 });
@@ -142,7 +143,7 @@ export const logoutRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "You are not authorized, please login",
+      AUTHORIZATION_ERROR_MESSAGE,
     ),
   },
 });
@@ -166,7 +167,7 @@ export const loggedinUserDetails = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "You are not authorized, please login",
+      AUTHORIZATION_ERROR_MESSAGE,
     ),
   },
 });
diff --git a/src/modules/categories/category.handlers.ts b/src/modules/categories/category.handlers.ts
index d999d70..a92f716 100644
--- a/src/modules/categories/category.handlers.ts
+++ b/src/modules/categories/category.handlers.ts
@@ -2,6 +2,7 @@ import { ActivityType, AuthRoles } from "@/common/enums";
 import { logActivity } from "@/common/helpers/activity-log.helper";
 import { generateMetadata } from "@/common/helpers/metadata.helper";
 import type { AppRouteHandler } from "@/common/lib/types";
+import { AUTHORIZATION_ERROR_MESSAGE } from "@/common/utils/constants";
 import * as HTTPStatusCodes from "@/common/utils/http-status-codes.util";
 import type { TSelectCategorySchema } from "@/db/schemas/category.model";
 
@@ -35,7 +36,7 @@ export const createCategory: AppRouteHandler<TCreateCategoryRoute> = async (
     return c.json(
       {
         success: false,
-        message: "You are not authorized, please login",
+        message: AUTHORIZATION_ERROR_MESSAGE,
       },
       HTTPStatusCodes.UNAUTHORIZED,
     );
diff --git a/src/modules/categories/category.routes.ts b/src/modules/categories/category.routes.ts
index c5afec4..409cf98 100644
--- a/src/modules/categories/category.routes.ts
+++ b/src/modules/categories/category.routes.ts
@@ -11,6 +11,7 @@ import {
 } from "@/common/middlewares/auth.middleware";
 import createErrorSchema from "@/common/schema/create-error.schema";
 import { metadataSchema } from "@/common/schema/metadata.schema";
+import { AUTHORIZATION_ERROR_MESSAGE, FORBIDDEN_ERROR_MESSAGE, VALIDATION_ERROR_MESSAGE } from "@/common/utils/constants";
 import * as HTTPStatusCodes from "@/common/utils/http-status-codes.util";
 import {
   insertCategorySchema,
@@ -55,14 +56,14 @@ export const createCategoryRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "The validation error(s)",
+      VALIDATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.UNAUTHORIZED]: jsonContent(
       z.object({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "You are not authorized, please login",
+      AUTHORIZATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.CONFLICT]: jsonContent(
       z.object({
@@ -73,7 +74,7 @@ export const createCategoryRoute = createRoute({
     ),
     [HTTPStatusCodes.UNPROCESSABLE_ENTITY]: jsonContent(
       createErrorSchema(insertCategorySchema),
-      "The validation error(s)",
+      VALIDATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.INTERNAL_SERVER_ERROR]: jsonContent(
       z.object({
@@ -181,21 +182,21 @@ export const updateCategoryRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "The validation error(s)",
+      VALIDATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.UNAUTHORIZED]: jsonContent(
       z.object({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "You are not authorized, please login",
+      AUTHORIZATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.FORBIDDEN]: jsonContent(
       z.object({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "You are not allowed to perform this action",
+      FORBIDDEN_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.INTERNAL_SERVER_ERROR]: jsonContent(
       z.object({
@@ -242,14 +243,14 @@ export const deleteCategoryRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "You are not authorized, please login",
+      AUTHORIZATION_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.FORBIDDEN]: jsonContent(
       z.object({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "You are not allowed to perform this action",
+      FORBIDDEN_ERROR_MESSAGE,
     ),
     [HTTPStatusCodes.INTERNAL_SERVER_ERROR]: jsonContent(
       z.object({
diff --git a/src/modules/group/group.routes.ts b/src/modules/group/group.routes.ts
index 778576f..2f7e016 100644
--- a/src/modules/group/group.routes.ts
+++ b/src/modules/group/group.routes.ts
@@ -12,6 +12,7 @@ import {
   AUTHORIZATION_ERROR_MESSAGE,
   FORBIDDEN_ERROR_MESSAGE,
   INTERNAL_SERVER_ERROR_MESSAGE,
+  RESOURCE_NOT_FOUND,
   VALIDATION_ERROR_MESSAGE,
 } from "@/common/utils/constants";
 import * as HTTPStatusCodes from "@/common/utils/http-status-codes.util";
@@ -127,7 +128,7 @@ export const getGroupById = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "Group with id does not exist",
+      RESOURCE_NOT_FOUND("group", idSchema),
     ),
     [HTTPStatusCodes.UNAUTHORIZED]: jsonContent(
       z.object({
@@ -186,7 +187,7 @@ export const updateGroupRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "Group with id does not exist",
+      RESOURCE_NOT_FOUND("group", idSchema),
     ),
     [HTTPStatusCodes.UNAUTHORIZED]: jsonContent(
       z.object({
@@ -235,7 +236,7 @@ export const deleteGroupRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "Group with id does not exist",
+      RESOURCE_NOT_FOUND("group", idSchema),
     ),
     [HTTPStatusCodes.UNAUTHORIZED]: jsonContent(
       z.object({
@@ -308,7 +309,7 @@ export const addUsersToGroupRoute = createRoute({
         success: z.boolean().default(false),
         message: z.string(),
       }),
-      "Group with id does not exist",
+      RESOURCE_NOT_FOUND("group", idSchema),
     ),
     [HTTPStatusCodes.UNPROCESSABLE_ENTITY]: jsonContent(
       createErrorSchema(insertGroupSchema),