> ## Documentation Index
> Fetch the complete documentation index at: https://docs.flexprice.io/llms.txt
> Use this file to discover all available pages before exploring further.

# COUNT

> Counts the number of distinct events (by ID) that match the criteria.

Step-by-Step Setup when creating a COUNT-based metered feature:

1. **Navigate to Features**
   * Go to Product Catalog → Features
   * Click "Add Feature"

2. **Basic Information**
   * **Name**: "API Calls" (or descriptive name)
   * **Type**: Select "Metered"

3. **Event Configuration**
   * **Event Name**: `api.calls` (must match your event data)
   * **Aggregation Function**: Count
   * **Aggregation Field**: Leave empty (not required for COUNT)

4. **Usage Settings**
   * **Usage Reset**: Periodic (for monthly limits) or Cumulative
   * **Unit Name**: `API call / API calls`

5. **Save Feature**

## Calculation Example

### Event Data

```json theme={null}
[
  {
    "event_id": "evt_001",
    "event_name": "api.calls",
    "external_customer_id": "customer_123",
    "timestamp": "2024-01-15T10:00:00Z"
  },
  {
    "event_id": "evt_002", 
    "event_name": "api.calls",
    "external_customer_id": "customer_123",
    "timestamp": "2024-01-15T10:05:00Z"
  },
  {
    "event_id": "evt_001", // Duplicate event ID
    "event_name": "api.calls",
    "external_customer_id": "customer_123", 
    "timestamp": "2024-01-15T10:10:00Z"
  }
]
```

### Calculation Process

1. **Event Matching**: All events with `event_name = "api.calls"`
2. **Deduplication**: Remove duplicate event IDs
   * `evt_001` (first occurrence)
   * `evt_002`
   * `evt_001` (duplicate - ignored)
3. **Count Result**: `2` (distinct events)

**Result**: `2 API calls`

## Use Cases

### API Request Tracking

**Perfect for**: RESTful APIs, GraphQL queries, webhook calls

```json theme={null}
{
  "event_name": "api.calls",
  "external_customer_id": "acme_corp"
}
```

### File Operations

**Perfect for**: File uploads, downloads, processing tasks

```json theme={null}
{
  "event_name": "file.uploads", 
  "external_customer_id": "user_456"
}
```

### Transaction Counting

**Perfect for**: Payment transactions, database operations, user actions

```json theme={null}
{
  "event_name": "transactions",
  "external_customer_id": "merchant_789"
}
```

### Feature Usage

**Perfect for**: Feature activations, button clicks, page views

```json theme={null}
{
  "event_name": "feature.usage",
  "external_customer_id": "customer_101"
}
```

### When to Use COUNT

✅ **Use COUNT when:**

* Tracking discrete events or actions
* You don't need to measure quantity/volume
* Simple occurrence-based billing
* High-volume event streams (best performance)

## Next Steps

* **[Creating a Metered Feature](/docs/event-ingestion/creating-a-metered-feature)** - Complete setup guide
* **[Sending Events](/docs/event-ingestion/sending-events)** - How to transmit COUNT events