# Project Testing

### Step 1: Go to your Winter Testnet project’s Sandbox checkout link

[https://sandbox-winter-checkout.onrender.com/?projectId={PROJECT\_ID}](https://sandbox-winter-checkout.onrender.com/?projectId=%7BPROJECT_ID%7D)

**NOTE:** If you are passing in any extraMintParams into your mint function, you will also need to pass through those extraMintParams here. [Go here for more information](https://docs.usewinter.com/front-end-integration/react).

### Step 2: Confirm the checkout is working

If your checkout is not rendering correctly, here are a few common fixes:

1. Make sure your Testnet project is active in the [business dashboard](https://business.usewinter.com/)
2. Make sure your Winter project is configured with your Testnet smart contract
3. If you have a custom Pricing function, make sure it's configured correctly
4. If you are passing in [extraMintParams](https://docs.usewinter.com/front-end-integration/react) to your mint function, make sure they are being passed in correctly

If you still need help, feel free to reach out to our team at <support@usewinter.com>!

### Step 3: Enter test credit card number

You can use testing card details to complete your checkout. For example, enter in "**4242424242424242**" for credit card number plus any CVC and expiration date. Click "Submit order"! You can find a full list of accepted testing card details [here](https://stripe.com/docs/testing).

{% embed url="<https://www.youtube.com/watch?v=Q3DifuHFQ_I>" %}
Demo checkout using testing credit card details
{% endembed %}

That's it! Congratulations on completing your Winter checkout test. Good luck on your launch!