# Usage

> What every response meters, and reading your key’s running totals from GET /v1/usage.

## What every response meters

Each generation response carries a `usage` object — the metered quantities for that call:

```json
{ "usage": { "input_chars": 42, "input_audio_seconds": 6.5, "output_audio_seconds": 3.2 } }
```

| Field | Meaning |
|---|---|
| `input_chars` | Characters of input text billed for the request. |
| `input_audio_seconds` | Seconds of audio you supplied (spoken history / reference clips in [converse](/conversations)). |
| `output_audio_seconds` | Seconds of audio generated for you. |

Log these on your side if you want per-request attribution — the API's own accounting is keyed to your API key, not to your users.

## Your running totals

`GET /v1/usage` returns the running totals for the key making the request:

```bash
curl -s https://api.kalpalabs.ai/v1/usage -H "Authorization: Bearer $KALPA_API_KEY"
```

```json
{
  "key_id": "acme",
  "requests": 1284,
  "input_chars": 91230,
  "input_audio_seconds": 411.0,
  "output_audio_seconds": 3120.5,
  "last_request_ts": 1751500000.0
}
```

`key_id` is the non-secret label of your key (it's what appears in our logs — the key itself never does). For invoicing-grade reports or historical breakdowns, write to [hello@kalpalabs.ai](mailto:hello@kalpalabs.ai).