Amex Insufficient Funds Test Card Numbers
Amex · Insufficient Funds: insufficient_funds is one of the most common soft declines in production. MockCard returns the matching decline_code in last_payment_error and a payment_intent.payment_failed webhook.
American Express uses 15-digit card numbers and separate CVV rules. MockCard generates Amex-shaped test data so formatting validators pass before you hit a real gateway.
When to use: Verify your UI shows a recoverable message, subscription retries backoff correctly, and you do not mark the order paid.
CI tip: Pair with do_not_honor and expired_card in a matrix test — gateways map codes differently.
Typical decline_code in webhook payloads: insufficient_funds.
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More Amex scenarios
Same scenario, other networks
Need webhook race conditions or 3DS abandonment? See payment failure testing and the API docs. Compare plans on pricing.
API example
const res = await fetch("https://mockcard.io/api/v1/generate", {
method: "POST",
headers: {
"Content-Type": "application/json",
"X-Api-Key": process.env.MOCKCARD_API_KEY ?? "",
},
body: JSON.stringify({
brand: "visa", // visa | mastercard | rupay | amex
scenario: "success", // success | insufficient_funds | 3ds_challenge …
}),
});
const card = await res.json();
// { card_number, expiry_month, expiry_year, cvv, brand, scenario }
console.log(card.card_number, card.cvv);