Skip to content
Docs/Verification Gates/Gate 9 — No Duplicate Receipt

Gate 9 — No Duplicate Receipt

QUICK GUIDE
Purpose

What this gate checks Gate 9 generates a perceptual image hash of your uploaded receipt photo and compares it against all previously submitted receipts in the system.

Best for

Understanding why a submission passed or failed

Read time

1 min

Next action

Find the failed gate, fix the issue, then resubmit

What this gate checks

Gate 9 generates a perceptual image hash of your uploaded receipt photo and compares it against all previously submitted receipts in the system. If the hash similarity score exceeds a threshold, the receipt is considered a duplicate and the submission fails. This applies regardless of the wallet address — the same physical receipt cannot be submitted twice even from different wallets.

Common failure reasons

  • Submitting the same receipt a second time after a previous failed submission
  • Two different users submitting photos of the same physical receipt
  • Submitting a photo of a photo of a receipt (the hash will still match)

How to ensure Gate 9 passes

Each submission requires a unique, original gas receipt that has never been submitted to GASCOIN before. Never resubmit a receipt — even if your previous submission failed on a different gate. Get a new receipt from a new gas purchase.