diff --git a/src/lib/api/adapters/entity.adapter.ts b/src/lib/api/adapters/entity.adapter.ts
index 225aee31..9e265261 100644
--- a/src/lib/api/adapters/entity.adapter.ts
+++ b/src/lib/api/adapters/entity.adapter.ts
@@ -110,6 +110,32 @@ export interface Character {
 	}>
 }
 
+/**
+ * Weapon key data for customizing weapons
+ */
+export interface WeaponKey {
+	id: string
+	granblue_id: number
+	name: {
+		en: string
+		ja: string
+	}
+	slug: string
+	series: number[]
+	slot: number
+	group: number
+	order: number
+}
+
+/**
+ * Query parameters for fetching weapon keys
+ */
+export interface WeaponKeyQueryParams {
+	series?: number
+	slot?: number
+	group?: number
+}
+
 /**
  * Canonical summon data from the game
  */
@@ -232,10 +258,28 @@ export class EntityAdapter extends BaseAdapter {
 		return Promise.all(promises)
 	}
 
+	/**
+	 * Gets weapon keys with optional filtering
+	 */
+	async getWeaponKeys(params?: WeaponKeyQueryParams): Promise<WeaponKey[]> {
+		const searchParams = new URLSearchParams()
+		if (params?.series !== undefined) searchParams.set('series', String(params.series))
+		if (params?.slot !== undefined) searchParams.set('slot', String(params.slot))
+		if (params?.group !== undefined) searchParams.set('group', String(params.group))
+
+		const queryString = searchParams.toString()
+		const url = queryString ? `/weapon_keys?${queryString}` : '/weapon_keys'
+
+		return this.request<WeaponKey[]>(url, {
+			method: 'GET',
+			cacheTTL: 3600000 // Cache for 1 hour - weapon keys rarely change
+		})
+	}
+
 	/**
 	 * Clears entity cache
 	 */
-	clearEntityCache(type?: 'weapons' | 'characters' | 'summons') {
+	clearEntityCache(type?: 'weapons' | 'characters' | 'summons' | 'weapon_keys') {
 		if (type) {
 			this.clearCache(`/${type}`)
 		} else {
@@ -243,6 +287,7 @@ export class EntityAdapter extends BaseAdapter {
 			this.clearCache('/weapons')
 			this.clearCache('/characters')
 			this.clearCache('/summons')
+			this.clearCache('/weapon_keys')
 		}
 	}
 }
diff --git a/src/lib/api/queries/entity.queries.ts b/src/lib/api/queries/entity.queries.ts
index 5fd9b920..9cf85bee 100644
--- a/src/lib/api/queries/entity.queries.ts
+++ b/src/lib/api/queries/entity.queries.ts
@@ -8,7 +8,7 @@
  */
 
 import { queryOptions } from '@tanstack/svelte-query'
-import { entityAdapter } from '$lib/api/adapters/entity.adapter'
+import { entityAdapter, type WeaponKeyQueryParams } from '$lib/api/adapters/entity.adapter'
 
 /**
  * Entity query options factory
@@ -72,6 +72,20 @@ export const entityQueries = {
 			enabled: !!id,
 			staleTime: 1000 * 60 * 60, // 1 hour - canonical data rarely changes
 			gcTime: 1000 * 60 * 60 * 24 // 24 hours
+		}),
+
+	/**
+	 * Weapon keys query options with optional filtering
+	 *
+	 * @param params - Optional filter parameters (series, slot, group)
+	 * @returns Query options for fetching weapon keys
+	 */
+	weaponKeys: (params?: WeaponKeyQueryParams) =>
+		queryOptions({
+			queryKey: ['weaponKeys', params?.series, params?.slot, params?.group] as const,
+			queryFn: () => entityAdapter.getWeaponKeys(params),
+			staleTime: 1000 * 60 * 60, // 1 hour - weapon keys rarely change
+			gcTime: 1000 * 60 * 60 * 24 // 24 hours
 		})
 }
 
@@ -98,5 +112,7 @@ export const entityKeys = {
 	characters: () => ['character'] as const,
 	character: (id: string) => [...entityKeys.characters(), id] as const,
 	summons: () => ['summon'] as const,
-	summon: (id: string) => [...entityKeys.summons(), id] as const
+	summon: (id: string) => [...entityKeys.summons(), id] as const,
+	weaponKeys: (params?: WeaponKeyQueryParams) =>
+		['weaponKeys', params?.series, params?.slot, params?.group] as const
 }