`v5/payment` error, empty card data, or "outcome: 0"

Last updated: June 24, 2026

Quick answer

Bad card read — usually a simulator or incomplete tap.

  1. Use a real device
  2. Call v5/payment (not v4)
  3. Ensure paymentCardData is valid base64-encoded JSON

See Payment Lifecycle.

Symptoms

  • outcome: 0

Solution

This usually indicates a bad card read — commonly from using the simulator or an incomplete tap. Use a real device, call v5/payment (not v4), and ensure paymentCardData is valid base64-encoded JSON.

Related articles

See also