diff --git a/apps/idlebiz/src/game/multiplier.ts b/apps/idlebiz/src/game/multiplier.ts
new file mode 100644
index 0000000..cefedb9
--- /dev/null
+++ b/apps/idlebiz/src/game/multiplier.ts
@@ -0,0 +1,69 @@
+import {
+  MultiplierSource,
+  type MultiplierType,
+  type PermanentMultiplier,
+  type Profile,
+  type TemporaryMultiplier,
+} from "@/game/types";
+import { mongo } from "@/lib/mongo";
+
+export async function addTemporaryMultiplier(
+  discordId: string,
+  value: number,
+  duration: number,
+  source: MultiplierSource,
+  type: MultiplierType
+) {
+  const now = new Date();
+  const expiredAt = new Date(now.getTime() + duration);
+
+  const multiplier: TemporaryMultiplier = {
+    value,
+    source,
+    type,
+    activatedAt: now,
+    expiredAt,
+  };
+
+  const client = await mongo();
+  const db = client.db();
+
+  return await db
+    .collection<Profile>("profiles")
+    .updateOne({ discordId: discordId }, { $push: { "multipliers.temporary": multiplier } });
+}
+
+export async function addPermanentMultiplier(
+  discordId: string,
+  value: number,
+  source: MultiplierSource,
+  type: MultiplierType
+) {
+  const now = new Date();
+
+  const multiplier: PermanentMultiplier = {
+    value,
+    source,
+    type,
+    activatedAt: now,
+  };
+
+  const client = await mongo();
+  const db = client.db();
+
+  return await db
+    .collection<Profile>("profiles")
+    .updateOne({ discordId: discordId }, { $push: { "multipliers.permanent": multiplier } });
+}
+
+export async function updateReferralBonusMultiplier(discordId: string, value: number) {
+  const client = await mongo();
+  const db = client.db();
+
+  return await db
+    .collection<Profile>("profiles")
+    .updateOne(
+      { discordId: discordId, "multipliers.permanent.source": MultiplierSource.ReferralBonus },
+      { $set: { "multipliers.permanent.$.value": value } }
+    );
+}
diff --git a/apps/idlebiz/src/lib/types/building.ts b/apps/idlebiz/src/game/types/building.ts
similarity index 100%
rename from apps/idlebiz/src/lib/types/building.ts
rename to apps/idlebiz/src/game/types/building.ts
diff --git a/apps/idlebiz/src/game/types/index.ts b/apps/idlebiz/src/game/types/index.ts
new file mode 100644
index 0000000..7bd18d1
--- /dev/null
+++ b/apps/idlebiz/src/game/types/index.ts
@@ -0,0 +1,5 @@
+export * from "./material";
+export * from "./building";
+export * from "./referral";
+export * from "./multiplier";
+export * from "./profile";
diff --git a/apps/idlebiz/src/lib/types/material.ts b/apps/idlebiz/src/game/types/material.ts
similarity index 100%
rename from apps/idlebiz/src/lib/types/material.ts
rename to apps/idlebiz/src/game/types/material.ts
diff --git a/apps/idlebiz/src/game/types/multiplier.ts b/apps/idlebiz/src/game/types/multiplier.ts
new file mode 100644
index 0000000..3dfeea1
--- /dev/null
+++ b/apps/idlebiz/src/game/types/multiplier.ts
@@ -0,0 +1,22 @@
+export enum MultiplierSource {
+  DailyReward = "dailyReward",
+  ReferralBonus = "referralBonus",
+  ReferralClaim = "referralClaim",
+}
+
+export enum MultiplierType {
+  MaterialProduction = "materialProduction",
+}
+
+type Multiplier = {
+  value: number;
+  source: MultiplierSource;
+  type: MultiplierType;
+  activatedAt: Date;
+};
+
+export type PermanentMultiplier = Multiplier;
+
+export type TemporaryMultiplier = Multiplier & {
+  expiredAt: Date;
+};
diff --git a/apps/idlebiz/src/game/types/profile.ts b/apps/idlebiz/src/game/types/profile.ts
new file mode 100644
index 0000000..58d348c
--- /dev/null
+++ b/apps/idlebiz/src/game/types/profile.ts
@@ -0,0 +1,12 @@
+// TODO
+import type { PermanentMultiplier, TemporaryMultiplier } from "@/game/types/multiplier";
+
+export type Profile = {
+  discordId: string;
+  multipliers: ProfileMultipliers;
+};
+
+export type ProfileMultipliers = {
+  permanent: PermanentMultiplier[];
+  temporary: TemporaryMultiplier[];
+};
diff --git a/apps/idlebiz/src/game/types/referral.ts b/apps/idlebiz/src/game/types/referral.ts
new file mode 100644
index 0000000..2e99973
--- /dev/null
+++ b/apps/idlebiz/src/game/types/referral.ts
@@ -0,0 +1,6 @@
+export type Referral = {
+  userId: string;
+  ownerId: string;
+  code: string;
+  createdAt: Date;
+};
diff --git a/apps/idlebiz/src/lib/types/index.ts b/apps/idlebiz/src/lib/types/index.ts
deleted file mode 100644
index 03f121a..0000000
--- a/apps/idlebiz/src/lib/types/index.ts
+++ /dev/null
@@ -1,2 +0,0 @@
-export * from "./material";
-export * from "./building";
diff --git a/apps/idlebiz/src/setup.ts b/apps/idlebiz/src/setup.ts
index 7747933..d32a648 100644
--- a/apps/idlebiz/src/setup.ts
+++ b/apps/idlebiz/src/setup.ts
@@ -1,6 +1,6 @@
+import type { Building } from "@/game/types/building";
+import type { Material } from "@/game/types/material";
 import { mongo } from "@/lib/mongo";
-import type { Building } from "@/lib/types/building";
-import type { Material } from "@/lib/types/material";
 import ms from "ms";
 
 (async () => {