Testing

Use the sandbox environment to test your integration without moving real money.

Environments

	Sandbox	Production
API base URL	`https://api.synapto.construction/v1/`	`https://api.synaptopay.com/v1/`
Dashboard	dashboard.synapto.construction	dashboard.synaptopay.com
JS SDK	`https://js.synapto.construction/synapto.js`	`https://js.synaptopay.com/synapto.js`

Create an API key in the sandbox Dashboard (Settings > Developer) and use the sandbox base URL. API keys use the same sk_live_ prefix in both environments.

Test card numbers

The sandbox accepts any valid card number. You can use these:

Card Type	Number
Visa	`4111111111111111`
Mastercard	`5431111111111111`

Use any future expiry date and any CVV (e.g. 999).

Simulating declines

To trigger a declined payment, use an amount less than 1.00 in the payment currency (less than 100 in the API's minor-unit format). For example, 0.50 GBP will be declined.

3D Secure test cards

Whether 3DS is triggered in sandbox depends on how your test account is configured. If you don't see 3DS challenges, contact [email protected] to check your account setup.

Use these cards to test 3D Secure authentication flows:

Card Number	Scenario
`4000000000002701`	3DS succeeds without challenge (frictionless)
`4000000000002503`	3DS succeeds with challenge (step-up)
`4000000000002925`	3DS authentication fails