10 Real-World Redis Use Cases Every Backend Engineer Should Know

Redis is a high‑performance key/value cache widely used in development and interviews.

This article presents ten practical Redis scenarios with code examples and implementation tips.

1. Count page visits

Define a key such as

OFFICIAL_INDEX_VISIT_COUNT

and use

INCR

to increment the count, or

INCRBY

to add a larger value.

<code>INCR OFFICIAL_INDEX_VISIT_COUNT</code>

<code>INCRBY OFFICIAL_INDEX_VISIT_COUNT 5</code>

2. Retrieve category tree

Cache the JSON representation of a category tree in Redis with a key like

MALL_CATEGORY_TREE

. A scheduled job populates the cache, and the API reads directly from this key, avoiding expensive recursive database queries.

3. Implement distributed lock

Use Redis

SET

with the

NX

and

PX

options to acquire a lock atomically. Example Java code:

<code>try{String result=jedis.set(lockKey,requestId,"NX","PX",expireTime);if("OK".equals(result)){return true;}return false;}finally{unlock(lockKey);}</code>

Be aware of edge cases where a lock may be released unintentionally.

4. Build leaderboards

Store ranking data in a Sorted Set. Use

ZADD

to add scores and

ZRANGE

(with

WITHSCORES

) to retrieve the ordered list.

<code>ZADD rank:score 100 "周星驰"
ZADD rank:score 90 "周杰伦"
ZADD rank:score 80 "周润发"
ZRANGE rank:score 0 -1 WITHSCORES</code>

<code>1) "周星驰"
2) "100"
3) "周杰伦"
4) "90"
5) "周润发"
6) "80"</code>

5. Record user login status

Store a user's login information in Redis with an expiration time (e.g., 1800 seconds). Subsequent requests check this key to verify authentication.

<code>jedis.set(userId, userInfo, 1800);</code>

6. Rate limiting

Track request counts per IP or user ID in Redis. Increment a counter for each request and set an expiration (e.g., one day). If the count exceeds a threshold, reject the request.

7. Bitmaps for statistics

Use Redis bitmap commands to record daily user activity.

SETBIT

marks a user as active on a specific date;

GETBIT

checks the status.

<code>SETBIT user:view:2024-01-17 123456 1</code>

<code>GETBIT user:view:2024-01-17 123456</code>

Iterate over user IDs to compute weekly or monthly active user metrics.

8. Cache acceleration

Implement a read‑through cache: query Redis first; if a miss occurs, fetch from the database, store the result in Redis, and return it. Be mindful of cache‑related issues such as penetration, breakdown, and avalanche.

9. Message queue

Redis Pub/Sub can serve as a lightweight message queue. Implement a Java

MessageListener

to consume messages from a channel.

<code>@Slf4j
@Component
public class RedisMessageListenerListener implements MessageListener {
    @Autowired
    private RedisTemplate<String, Object> redisTemplate;

    @Override
    public void onMessage(Message message, byte[] pattern) {
        String channel = new String(pattern);
        RedisSerializer<?> valueSerializer = redisTemplate.getValueSerializer();
        Object deserialize = valueSerializer.deserialize(message.getBody());
        if (deserialize == null) return;
        String md5DigestAsHex = DigestUtils.md5DigestAsHex(deserialize.toString().getBytes(StandardCharsets.UTF_8));
        Boolean result = redisTemplate.opsForValue().setIfAbsent(md5DigestAsHex, "1", 20, TimeUnit.SECONDS);
        if (Boolean.TRUE.equals(result)) {
            log.info("Received result: {}", deserialize.toString());
        } else {
            log.info("Other service processing");
        }
    }
}
</code>

10. Generate global IDs

Use

INCRBY

on a dedicated key to obtain atomic, incrementing identifiers, useful for sharding or batch ID allocation.

<code>INCRBY userid 10000</code>