# Credits & Billing

> Tchavi uses a credit-based billing system — each API request consumes credits based on the model used and the number of tokens processed.

- Canonical: https://tchavi.com/en/docs/credits

---


Tchavi uses a credit-based billing system. Each API request consumes credits based on the model used and the number of tokens processed.

## How credits are calculated

- **Chat models:** Credits = (input_tokens × rate + output_tokens × rate) per 1K tokens
- **Image models:** Flat credit cost per image based on resolution
- **TTS (text-to-speech):** Credits per 1K characters of input text
- **Transcription (Whisper):** Credits per minute of audio
- **Video models:** Credits per second of video, varies by resolution (some models add a surcharge when audio is generated)

## Response headers

Every API response includes metadata headers:

| Header                      | Description                                        |
| --------------------------- | -------------------------------------------------- |
| `X-Credits-Used`            | Credits consumed by this request                   |
| `X-Credits-Remaining`       | Your current credit balance                        |
| `X-RateLimit-RPM-Limit`     | Your requests-per-minute limit                     |
| `X-RateLimit-RPM-Remaining` | Requests remaining in the current minute           |
| `X-RateLimit-TPM-Limit`     | Your tokens-per-minute limit                       |
| `X-RateLimit-TPM-Remaining` | Token budget remaining in the current minute       |
| `X-Request-Id`              | Unique request ID for support/debugging            |
| `Retry-After`               | Seconds to wait before retrying (on 429 responses) |

<Callout type="note">
**Example credit calculation.** A `gpt-4o-mini` request with 500 input tokens + 200 output tokens at the Budget tier (e.g. 1 cr/1K input, 2 cr/1K output) costs:

```text
(500/1000 × 1) + (200/1000 × 2) = 0.9 credits
```

→ rounded up to **1 credit**. The exact rate for each model is shown in the [Models table](/en/docs/models).

</Callout>

## Recharging

Buy credit packs from your [billing dashboard](/billing) using Wave, Orange Money, MTN MoMo, and 30+ mobile money operators. Credits are added instantly after payment.

See also [Rate Limits](/en/docs/rate-limits) and [Error Handling](/en/docs/errors).