diff --git a/.config/example.yml b/.config/example.yml
index 03ee6e272..e206ccd34 100644
--- a/.config/example.yml
+++ b/.config/example.yml
@@ -57,7 +57,7 @@ db:
 redis:
   host: localhost
   port: 6379
-  #family: 0  # 0=Both, 4=IPv4, 6=IPv6
+  #family: dual  # can be either a number or string (0/dual, 4/ipv4, 6/ipv6)
   #pass: example-pass
   #prefix: example-prefix
   #db: 1
diff --git a/packages/backend/src/config/types.ts b/packages/backend/src/config/types.ts
index 89eafb093..cd74df343 100644
--- a/packages/backend/src/config/types.ts
+++ b/packages/backend/src/config/types.ts
@@ -1,5 +1,10 @@
 /**
- * ユーザーが設定する必要のある情報
+ * IP address family
+ */
+export type IpFamily = 'ipv4' | 'ipv6' | 'dual';
+
+/**
+ * Configuration options set up by the user
  */
 export type Source = {
 	repository_url?: string;
@@ -19,7 +24,7 @@ export type Source = {
 	redis: {
 		host: string;
 		port: number;
-		family?: number;
+		family?: number | IpFamily;
 		pass: string;
 		db?: number;
 		prefix?: string;
@@ -47,7 +52,7 @@ export type Source = {
 
 	id: string;
 
-	outgoingAddressFamily?: 'ipv4' | 'ipv6' | 'dual';
+	outgoingAddressFamily?: IpFamily;
 
 	deliverJobConcurrency?: number;
 	inboxJobConcurrency?: number;
diff --git a/packages/backend/src/db/redis.ts b/packages/backend/src/db/redis.ts
index cd9c81eb3..e576f5e35 100644
--- a/packages/backend/src/db/redis.ts
+++ b/packages/backend/src/db/redis.ts
@@ -1,11 +1,21 @@
 import Redis from 'ioredis';
 import config from '@/config/index.js';
+import { IpFamily } from '@/config/types.js';
 
-export function createConnection() {
+function getRedisFamily(family?: IpFamily | number): number {
+	switch (family) {
+		case 'ipv4': return 4;
+		case 'ipv6': return 6;
+		case 'dual': return 0;
+		default: return family ?? 0;
+	}
+}
+
+export function createConnection(): Redis.Redis {
 	return new Redis({
 		port: config.redis.port,
 		host: config.redis.host,
-		family: config.redis.family ?? 0,
+		family: getRedisFamily(config.redis.family),
 		password: config.redis.pass,
 		keyPrefix: `${config.redis.prefix}:`,
 		db: config.redis.db || 0,