invalidReceiptError (error code 8): Invalid receipt

• The backend answered 7103 (invalid receipt token) or, on iOS, 7712 (the purchased product is missing from the Apple receipt). Both map to invalidReceiptError (BackendErrorCode.swift).
• The receipt was made by a build with a different bundle ID or package name than the app configured on the backend.
• A StoreKit testing receipt signed by Xcode's local certificate, not by Apple, reached a backend that does not know that certificate (Apple: set up StoreKit testing).
• A purchase token that Google Play says is invalid, or a cancelled pending purchase.
• Android with Amazon: the SDK could not get the Amazon receipt data from the backend.

• Do not retry. A 4xx answer tells the SDK the receipt can never be accepted, so it finishes the transaction.
• Do not grant access from the error. Show "We could not verify your purchase" and point the customer to support.
• Log the app user ID and the underlying message. For a paying customer, check the store's own record and grant access by hand if needed.

// Swift
do {
  let result = try await Purchases.shared.purchase(package: package)
} catch let error as ErrorCode where error == .invalidReceiptError {
  // handle invalid receipt
}

// Kotlin
if (error.code == PurchasesErrorCode.InvalidReceiptError) { /* ... */ }

On RevenueDot: RevenueDot answers HTTP 400 with code 7103 when the body has neither fetch_token nor app_transaction, when a StoreKit 2 transaction's signature or bundle ID does not verify, when Google says the purchase token is invalid or product_ids is missing for a one-time product, and when a Test Store token is malformed. Temporary store failures never answer 7103: they answer 5xx so the SDK retries. See 4xx or 5xx on a receipt.