There is no separate sandbox URL - use the same API endpoint with sandbox credentials. Create a sandbox website in the Merchant Portal to get test API keys. Use test card 4111 1111 1111 1111 (Visa, Success) with any future expiry and any 3-digit CVC. Note: Apple Pay cannot be tested in sandbox mode due to Apple restrictions.
For the full guide including all test card numbers, error codes, and troubleshooting, visit our developer documentation: https://docs.costplus.io/docs/getting-started/testing
Need help? Contact support@costplus.io.