Stripe decline code: testmode_decline

One of Stripe's published test card numbers, such as 4000 0000 0000 0002, was submitted to a live-mode request. Live mode declines them by design so that test data can never produce a real charge. In practice it almost always means the wrong API key is in play, or a seeded fixture leaked into a production environment.

• A live secret key paired with a test card, usually because environments were crossed during a deploy.
• Seed or fixture data containing test PANs running against production.
• A staging environment pointed at live keys.
• A developer testing against production deliberately, which is what the code exists to prevent.

1. Check which key the request used. A `sk_live_` key with a test card produces this every time, and the mismatch is the actual defect.
2. Keep test and live keys in separate environment configurations, and never fall back from one to the other.
3. Strip test PANs out of any fixture data that could run against production.
4. Use Stripe's designated test cards in test mode only — that is the environment where their documented decline behaviours work.

• Stripe card_declinedcard_declined
• Stripe generic_declinegeneric_decline
• ISO 8583 14Invalid card number (no such number)

• Card test toolkit

Does this mean my Stripe account is in test mode?

The opposite. Live mode rejected a test card, so the request was live and the card was not. Look at which API key the request carried — a `sk_live_` key that received a test PAN is the situation this code describes.