Skip to main content
This page is for developers and QA running sandbox orders through headless card and Apple Pay. Separate from the White-Label API and Meld Checkout testing credentials, which cover the widget flows, and from Virtual Account Flow Testing Credentials.

​
What you can verify

The order call, the capture surface appearing in your app, the SDK’s events, and the webhook chain. How far past that you can go depends on the provider’s own sandbox, and differs by payment method — see each section below.

​
Before you start

Base URL: https://api-sb.meld.io
  • A sandbox API key with payment access
  • Headless onramps enabled on your sandbox account
  • Sandbox credentials for the provider you are testing, on your Meld account
  • A webhook endpoint reachable from the internet, configured in the dashboard
  • A test customer, KYC-approved — see KYC Testing
Sandbox coverage is narrower than production, and a US test customer is the most common reason an otherwise correct integration returns no quotes. Quote first and use whatever country and currency pair comes back with the provider you intend to test.

​
Test the card flow

Test cards against Banxa. It is the provider with a published headless card sandbox, and the cards below are its.
  1. Quote for your country, currency pair and amount, and pick the Banxa quote.
  2. Create the order with paymentMethodType: CREDIT_DEBIT_CARD.
  3. Mount the order in your client.
  4. Pay with one of the cards below.

​
Successful authorization

​
Failed and declined authorization

Run at least one decline as well as one success. A decline is the path most integrations get wrong: the surface stays mounted and the customer retries, so nothing should be torn down and no order should be credited.
Other providers’ card sandboxes behave differently and some reject transactions that would succeed in production. Where a provider publishes test cards, they are listed under its section in White-Label API and Meld Checkout testing credentials.

​
Test Apple Pay

You can present the sheet in sandbox. You cannot settle a payment with it. Presentation is the whole of what sandbox Apple Pay verifies — the order, the sheet, and the events around it. Treat a settled Apple Pay purchase as a production check.
  1. Quote for a country and currency pair that return an Apple Pay provider.
  2. Create the order with paymentMethodType: APPLE_PAY.
  3. Check canPresentApplePay(), then mount.
What to confirm: The iOS Simulator presents and authorises the sheet but cannot produce a decryptable payment token, so it exercises mounting, events and the cancel path and nothing beyond. A real device with an Apple sandbox tester account gets you a genuine authorisation, and still no settlement.

​
Verify the result

For card, check all three. Each catches something the others do not. The transaction is created asynchronously, so it will not exist the instant the order call returns. Wait for TRANSACTION_CRYPTO_PENDING.