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

# Test mode

> Validate your integration with deterministic API scenarios.

Use a `chk_test_` API key to validate your integration before you send live inference traffic. Test requests go to the same base URL, `https://api.trycarhub.com`, and follow the same authentication, idempotency, job, credit-reservation and webhook paths as live requests.

Test and live credit balances are separate. A test request returns `livemode: false` in its job. It never runs a production model or consumes live credits.

## Select a scenario

Set `X-Carhub-Test-Scenario` on an inference request. Omit the header for the endpoint's deterministic successful fixture.

| Header value           | Expected outcome                                                                  |
| ---------------------- | --------------------------------------------------------------------------------- |
| *(omit header)*        | Successful job using the default fixture.                                         |
| `empty_result`         | Successful job with no detections or readings.                                    |
| `low_confidence`       | Successful job with confidence values below `0.5`.                                |
| `model_error`          | Job settles as `failed`; its credit reservation is released.                      |
| `slow`                 | Completion takes about 30 seconds; use it to verify polling and webhook handling. |
| `insufficient_credits` | Submission returns `402 insufficient_credits`; no job is created.                 |

Some scenarios are not meaningful for every endpoint. CarHub rejects an unsupported scenario with `400 test_scenario_not_supported` rather than silently falling back to a default response.

## Example

```bash theme={null}
curl -sS -X POST "https://api.trycarhub.com/v1/plate/read" \
  -H "Authorization: Bearer $CARHUB_TEST_KEY" \
  -H "Idempotency-Key: 8b1f1c2e-9d3a-4a51-9f0c-1c9a2f6d7b44" \
  -H "X-Carhub-Test-Scenario: low_confidence" \
  -F "image=@plate.jpg"
```

<Tip>Test both an immediate response and a queued job. Use `slow` to confirm that your client keeps polling or accepts the corresponding webhook after `wait=true` reaches its 30-second limit.</Tip>

Use a new idempotency key for each distinct test case. Reuse the same key only when you are verifying retry behaviour for the same payload.