# Testing

Build and test your integration in **test mode**, where no real money moves. There is
one API host: your **key prefix** selects the mode.

| Mode | Base URL | Key |
| --- | --- | --- |
| Test | `https://api.paymee.online/api/v1` | `sk_test_…` |
| Live | `https://api.paymee.online/api/v1` | `sk_live_…` |

Test mode is fully separate from live mode: its own sessions and refunds, its own webhook
endpoint and signing secret, and its own exchange rates. Switch your dashboard to **test
mode** to configure them. Every test-mode object and event carries `livemode: false`.

## Test cards

Use these cards on the hosted checkout page in test mode. You enter them on the payment
page — Paymee never asks you to send card numbers to the API.

| Brand | Card number | Expiry | CVV |
| --- | --- | --- | --- |
| Visa | `4509 2111 1111 1119` | `12/26` | `748` |
| Mastercard | `5440 2127 1111 1110` | `12/26` | `665` |

**3-D Secure code** for every test card: `12345`.

Whether a test payment succeeds or is declined is decided by the acquirer's test system;
there are no cards or amounts that force a decline. To check your failure handling
without a declined payment, send a `session.attempt_failed` or `session.failed`
[test event](/guides/webhooks/#testing-your-endpoint) to your endpoint.

:::caution
These are **test-mode** cards only. Don't put them in your application code or your test
suite — they belong on the hosted checkout page during manual or automated checkout
testing.
:::

## End-to-end test flow

1. Create a session with your `sk_test_…` key (see [Quickstart](/guides/quickstart/)).
2. Open the returned `checkout_url`.
3. Pay with a test card above; complete 3-D Secure with `12345`.
4. Confirm your endpoint receives a `session.succeeded` [webhook](/guides/webhooks/) and
   that you verify its signature.
5. [Refund](/guides/refunds/) the session through the API and confirm you receive
   `refund.succeeded`.

When everything works end to end, follow the [Going live](/guides/going-live/) checklist.

Source: https://docs.paymee.online/guides/testing/