# ReferencedPaymentNonexistence > Payment due by the agreed deadline has not been made. > For the complete documentation index, see [llms.txt](/llms.txt). Markdown versions of documentation pages are available by appending `.md` to the page URL. Source: https://dev.flare.network/fdc/attestation-types/referenced-payment-nonexistence Assertion that a specific payment, agreed upon to be completed by a certain deadline, has **not been made**. If confirmed, it shows that no transaction meeting the specified criteria (address, amount, reference) was found within the given block range. This Information can be used, for example, to justify the liquidation of funds locked in a smart contract on Songbird if a payment is missed. ## Supported chains[​](#supported-chains "Direct link to Supported chains") Network Type Supported Chains **Mainnet** `BTC` (Bitcoin), `DOGE` (Dogecoin), `XRP` (XRP Ledger) **Testnet** `testBTC` (Bitcoin Testnet v3), `testDOGE`, `testXRP` ## Request[​](#request "Direct link to Request") Field Solidity Type Description `minimalBlockNumber` `uint64` The block number to start the search range. `deadlineBlockNumber` `uint64` The block number to include as the end of the search range. `deadlineTimestamp` `uint64` The timestamp to include as the end of the search range. `destinationAddressHash` `bytes32` The standard hash of the address where the payment was expected. `amount` `uint256` The required payment amount in minimal units. `standardPaymentReference` `bytes32` The standard payment reference associated with the payment. Must not be zero. `checkSourceAddresses` `bool` If true, the source addresses root is checked. `sourceAddressesRoot` `bytes32` The root of the Merkle tree of the source addresses. note **Standard Addresses Root** is the root of the Merkle tree build on double keccak256 hashes of the all source addresses of the transaction. ## Response[​](#response "Direct link to Response") Field Solidity Type Description `minimalBlockTimestamp` `uint64` The timestamp of the block at `minimalBlockNumber`. `firstOverflowBlockNumber` `uint64` The block number immediately after the `deadlineBlockNumber`. `firstOverflowBlockTimestamp` `uint64` The timestamp of the `firstOverflowBlockNumber`. - **`firstOverflowBlockNumber`**: This is the first block with a height greater than `deadlineBlockNumber` and a timestamp later than `deadlineTimestamp`. - The search range includes blocks from `minimalBlockNumber` (inclusive) to `firstOverflowBlockNumber` (exclusive). ## Verification process[​](#verification-process "Direct link to Verification process") 1. **Block Confirmation**: - If the `firstOverflowBlock` cannot be determined or lacks the required [number of confirmations](#finality), the request is rejected. - The request is also rejected if `firstOverflowBlockNumber` is less than or equal to `minimalBlockNumber`. 2. **Search Range**: - The search range includes blocks from `minimalBlockNumber` to `firstOverflowBlockNumber` (exclusive). - If the verifier does not have complete visibility of all blocks in this range, the request is rejected. 3. **Transaction Validation**: - The request is confirmed if **no transaction** meeting the specified criteria (address, source addresses root, amount, reference) is found within the specified block range. - The criteria and timestamp interpretation are specific to each chain. The verification process is chain-specific, with details described below. ### UTXO chains (Bitcoin and Dogecoin)[​](#utxo-chains-bitcoin-and-dogecoin "Direct link to UTXO chains (Bitcoin and Dogecoin)") #### Transaction Criteria[​](#transaction-criteria "Direct link to Transaction Criteria") - The transaction **must not be a coinbase transaction**. - The transaction must include the specified [standard payment reference](#standard-payment-reference). - If `checkSourceAddresses` is set to true, the `sourceAddressesRoot` of the transaction must match the specified `sourceAddressesRoot`. - The sum of all output values sent to the specified address **minus** the sum of all input values from the same address must be **greater or equal to the specified `amount`**. - Typically, the sum of input values for the specified address is zero. #### Timestamp[​](#timestamp "Direct link to Timestamp") - Uses the **mediantime** of the block. ### Account-based chains (XRPL)[​](#account-based-chains-xrpl "Direct link to Account-based chains (XRPL)") #### Transaction Criteria[​](#transaction-criteria-1 "Direct link to Transaction Criteria") - The transaction must be of type **Payment**. - The transaction must include the specified [standard payment reference](#standard-payment-reference). - If `checkSourceAddresses` is set to true, the `sourceAddressesRoot` of the transaction must match the specified `sourceAddressesRoot`. - One of the following conditions must hold: - The transaction status is `SUCCESS` and the amount received by the specified address is greater or equal to the specified `amount`. - The transaction status is `RECEIVER_FAILURE` and the specified address would have received an amount greater or equal to the specified `amount` if the transaction had succeeded. #### Timestamp[​](#timestamp-1 "Direct link to Timestamp") - Uses the **close\_time** of the ledger, converted to UNIX time. Lowest used timestamp For the `lowestUsedTimestamp` parameter, the value of `minimalBlockTimestamp` is used. ## Standard payment reference[​](#standard-payment-reference "Direct link to Standard payment reference") A standard payment reference is defined as a 32-byte sequence that can be added to a payment transaction, in the same way that a payment reference is attached to a traditional banking transaction. ### Bitcoin and Dogecoin[​](#bitcoin-and-dogecoin "Direct link to Bitcoin and Dogecoin") - Uses `OP_RETURN` to store references. - A transaction is considered to have a `standardPaymentReference` defined if it has: - Exactly one output UTXO with `OP_RETURN` script, and - The script is of the form `OP_RETURN ` or `6a` in hex, where the length of the reference is 32 bytes. - Then `0x` is the `standardPaymentReference`. ### XRPL[​](#xrpl "Direct link to XRPL") - Uses the `memoData` field. - A transaction has a `standardPaymentReference` if it has: - Exactly one [Memo](https://xrpl.org/transaction-common-fields.html#memos-field), and - The `memoData` of this field is a hex string that represents a byte sequence of exactly 32 bytes. - This 32-byte sequence defines the `standardPaymentReference`. ## Finality[​](#finality "Direct link to Finality") Blockchains have varying confirmation depths to consider blocks as final. Chain `chainId` Confirmations required Confirmation time Bitcoin 0 6 ≈60 mins Dogecoin 2 60 ≈60 mins XRPL 3 3 ≈12 seconds ## Contract Interface[​](#contract-interface "Direct link to Contract Interface") For the complete interface definition, see [`IReferencedPaymentNonexistence`](/fdc/reference/IReferencedPaymentNonexistence).