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Test Cards

Use these card numbers in test mode to simulate payment outcomes through the Flowlix sandbox. All test cards work with any future expiration date and any 3-digit CVC (4-digit for Amex).
Test cards only work with test mode API keys (fl_test_sk_). Using them with a live key will be rejected by the upstream provider.
Decline outcomes in sandbox are determined by the upstream sandbox processor, not by Flowlix client-side PAN matching. The cards below are the ones currently mapped in the sandbox configuration. Other PANs may succeed, fall through to generic_decline, or behave unpredictably — only rely on the cards listed here for deterministic test outcomes.

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Successful payments

Card numberBrandDescription
4111111111111111VisaStandard successful payment

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Declined payments

Card numberDecline codeDescription
4000000000000002do_not_honorThe issuer declines without a specific reason.
4000000000009995insufficient_fundsThe card has insufficient funds.
If you need to exercise other decline codes (expired_card, invalid_number, lost_card, stolen_card, card_velocity_exceeded, generic_decline) end-to-end, file a request to add them to the sandbox — they are produced by the upstream provider’s mock environment, not by a Flowlix-side PAN lookup.

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Using test cards

All test cards accept:
  • Any future expiration date (e.g. 12/2027)
  • Any CVC (e.g. 123 for Visa/MC, 1234 for Amex)
  • Any cardholder name

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Example: successful payment

curl -X POST https://api.flowlix.dev/v1/payments \
  -H "Authorization: Bearer fl_test_sk_abc123" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
    "amount": 2000,
    "currency": "eur",
    "card": {
      "number": "4111111111111111",
      "exp_month": 12,
      "exp_year": 2027,
      "cvc": "123",
      "holder_name": "Test User"
    },
    "customer": {
      "email": "test@example.com",
      "first_name": "Test",
      "last_name": "User",
      "country": "DE",
      "phone": "+491701234567",
      "address": "Kurfuerstendamm 21",
      "city": "Berlin",
      "zip": "10719"
    }
  }'
Response: 201 Created with "status": "pending". Poll GET /v1/payments/{id} until succeeded.

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Example: declined payment

curl -X POST https://api.flowlix.dev/v1/payments \
  -H "Authorization: Bearer fl_test_sk_abc123" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
    "amount": 2000,
    "currency": "eur",
    "card": {
      "number": "4000000000009995",
      "exp_month": 12,
      "exp_year": 2027,
      "cvc": "123",
      "holder_name": "Test User"
    },
    "customer": {
      "email": "test@example.com",
      "first_name": "Test",
      "last_name": "User",
      "country": "DE",
      "phone": "+491701234567",
      "address": "Kurfuerstendamm 21",
      "city": "Berlin",
      "zip": "10719"
    }
  }'
Response: 201 Created with "status": "pending". After processing, a subsequent GET /v1/payments/{id} returns the failed Payment object with the decline reason populated: 
{
  "id": "pay_a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "status": "failed",
  "decline_code": "insufficient_funds",
  "decline_message": "The card has insufficient funds to complete the purchase."
}

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Testing the HPP flow

Test cards also work on the Hosted Payment Page. Create an HPP session with a test key, open the redirect_url in your browser, and enter any test card number.

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Tips

  • Test every decline scenario your integration might encounter in production.
  • Verify your error messages — make sure you show helpful, customer-friendly messages for each decline code.
  • Always poll GET /v1/payments/{id} for the terminal status — 201 Created is not a success signal.
  • Test edge cases like expired cards and rate-limit responses, not just the happy path.