> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/upstash/redis-js/llms.txt
> Use this file to discover all available pages before exploring further.

# HINCRBY

> Increment a hash field by a number

## Usage

Increments the number stored at `field` in the hash stored at `key` by `increment`. If the field does not exist, it is set to 0 before performing the operation.

```typescript theme={null}
await redis.hincrby(key, field, increment);
```

## Parameters

<ParamField path="key" type="string" required>
  The key of the hash
</ParamField>

<ParamField path="field" type="string" required>
  The field in the hash to increment
</ParamField>

<ParamField path="increment" type="number" required>
  The increment value. Can be positive or negative to increment or decrement the field.
</ParamField>

## Response

<ResponseField name="value" type="number">
  The value of the field after the increment operation.
</ResponseField>

## Examples

### Increment a counter

```typescript theme={null}
import { Redis } from '@upstash/redis';

const redis = new Redis({
  url: process.env.UPSTASH_REDIS_REST_URL!,
  token: process.env.UPSTASH_REDIS_REST_TOKEN!,
});

// Initialize counter
await redis.hset('user:1000:stats', { loginCount: 0 });

// Increment login counter
const newCount = await redis.hincrby('user:1000:stats', 'loginCount', 1);
console.log(newCount); // 1

// Increment again
const count2 = await redis.hincrby('user:1000:stats', 'loginCount', 1);
console.log(count2); // 2
```

### Increment non-existent field

```typescript theme={null}
// Field doesn't exist, starts at 0
const views = await redis.hincrby('article:500', 'views', 1);
console.log(views); // 1
```

### Decrement by using negative increment

```typescript theme={null}
// Set initial inventory
await redis.hset('product:200', { inventory: 100 });

// Decrease inventory by 5
const remaining = await redis.hincrby('product:200', 'inventory', -5);
console.log(remaining); // 95
```

### Track multiple metrics

```typescript theme={null}
// Track user activity metrics
await redis.hincrby('user:1000:activity', 'postsCreated', 1);
await redis.hincrby('user:1000:activity', 'commentsCreated', 1);
await redis.hincrby('user:1000:activity', 'likesGiven', 1);

const activity = await redis.hgetall('user:1000:activity');
console.log(activity);
// { postsCreated: 1, commentsCreated: 1, likesGiven: 1 }
```

### Implement rate limiting

```typescript theme={null}
const incrementApiCall = async (userId: string): Promise<number> => {
  const key = `ratelimit:${userId}:${Date.now() / 1000 / 60 | 0}`; // per minute
  return await redis.hincrby(key, 'requests', 1);
};

const requests = await incrementApiCall('user:1000');
if (requests > 100) {
  console.log('Rate limit exceeded');
}
```

### Track votes or scores

```typescript theme={null}
// Upvote a post
await redis.hincrby('post:1000', 'upvotes', 1);

// Downvote a post
await redis.hincrby('post:1000', 'downvotes', 1);

// Calculate score
const post = await redis.hgetall('post:1000');
const score = (post?.upvotes || 0) - (post?.downvotes || 0);
console.log(`Score: ${score}`);
```

### Increment by larger amounts

```typescript theme={null}
// Add points to user score
await redis.hincrby('user:1000:score', 'points', 100);

// Bonus points
await redis.hincrby('user:1000:score', 'points', 500);

const totalPoints = await redis.hget('user:1000:score', 'points');
console.log(totalPoints); // 600
```

### Analytics tracking

```typescript theme={null}
// Track daily page views
const today = new Date().toISOString().split('T')[0];
await redis.hincrby('analytics:pageviews', today, 1);

// Track by page
await redis.hincrby('analytics:pages', '/home', 1);
await redis.hincrby('analytics:pages', '/about', 1);

const pageStats = await redis.hgetall('analytics:pages');
console.log(pageStats); // { '/home': 1, '/about': 1 }
```

## Notes

* The operation is atomic
* If the hash or field doesn't exist, it's created with the field set to 0 before incrementing
* Only works with integer values
* For floating-point increments, use `HINCRBYFLOAT`
* An error is returned if the field contains a value of the wrong type or a string that cannot be represented as an integer

## See Also

* [HSET](/api/commands/hset) - Set hash field values
* [HGET](/api/commands/hget) - Get a hash field value
* [HINCRBY](/api/commands/hincrby) - Increment a hash field