Transaction Common Fields

Every transaction has the same set of common fields, plus additional fields based on the transaction type. Field names are case-sensitive. The common fields for all transactions are:

: The PreviousTxnID field of transactions was replaced by the AccountTxnID field. This String / Hash256 field is present in some historical transactions. This is unrelated to the field also named PreviousTxnID in some ledger objects.

AccountTxnID

The AccountTxnID field lets you chain your transactions together, so that a current transaction is not valid unless the previous transaction sent from the same account has a specific transaction hash.

Unlike the PreviousTxnID field, which tracks the last transaction to modify an account (regardless of sender), the AccountTxnID tracks the last transaction sent by an account. To use AccountTxnID, you must first enable the asfAccountTxnID flag, so that the ledger keeps track of the ID for the account's previous transaction. (PreviousTxnID, by comparison, is always tracked.)

One situation in which this is useful is if you have a primary system for submitting transactions and a passive backup system. If the passive backup system becomes disconnected from the primary, but the primary is not fully dead, and they both begin operating at the same time, you could potentially have serious problems like some transactions sending twice and others not at all. Chaining your transactions together with AccountTxnID ensures that, even if both systems are active, only one of them can submit valid transactions at a time.

The AccountTxnID field cannot be used on transactions that use Tickets. Transactions that use AccountTxnID cannot be placed in the transaction queue.

Auto-fillable Fields

Some fields can be automatically filled in before a transaction is signed, either by a rippled server or by a client library. Auto-filling values requires an active connection to the XRP Ledger to get the latest state, so it cannot be done offline. The details can vary by library, but auto-filling always provides suitable values for at least the following fields:

• Fee - Automatically fill in the Transaction Cost based on the network.

  Note

  When using rippled's sign command, you can limit the maximum possible auto-filled value, using the fee_mult_max and fee_div_max parameters.)

• Sequence - Automatically use the next sequence number for the account sending the transaction.

For a production system, we recommend not leaving these fields to be filled by the server. For example, if transaction costs become high due to a temporary spike in network load, you may want to wait for the cost to decrease before sending some transactions, instead of paying the temporarily-high cost.

The Paths field of the Payment transaction type can also be automatically filled in.

Flags Field

The Flags field can contain various options that affect how a transaction should behave. The options are represented as binary values that can be combined with bitwise-or operations to set multiple flags at once.

To check whether a transaction has a given flag enabled, use the bitwise-and operator on the flag's value and the Flags field. A result of zero indicates the flag is disabled, and a result equal to the flag value indicates the flag is enabled. (If you got any other result, you did something wrong.)

Most flags only have meaning for a specific transaction type. The same bitwise value may be reused for flags on different transaction types, so it is important to pay attention to the TransactionType field when setting and reading flags.

Bits that are not defined as flags MUST be 0. (The fix1543 amendment enforces this rule on some transaction types. Most transaction types enforce this rule by default.)

Global Flags

The only flag that applies globally to all transactions is as follows:

When using the sign method (or submit method in "sign-and-submit" mode), rippled adds a Flags field with tfFullyCanonicalSig enabled unless the Flags field is already present. The tfFullyCanonicalSig flag is not automatically enabled if Flags is explicitly specified. The flag is not automatically enabled when using the sign_for method to add a signature to a multi-signed transaction.

Flag Ranges

A transaction's Flags field can contain flags that apply at different levels or contexts. Flags for each context are limited to the following ranges:

Memos Field

The Memos field includes arbitrary messaging data with the transaction. It is presented as an array of objects. Each object has only one field, Memo, which in turn contains another object with one or more of the following fields:

The MemoType and MemoFormat fields should only consist of the following characters: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~:/?#[]@!$&'()*+,;=%

The Memos field is limited to no more than 1 KB in size (when serialized in binary format).

Example of a transaction with a Memos field:

{
    "TransactionType": "Payment",
    "Account": "rMmTCjGFRWPz8S2zAUUoNVSQHxtRQD4eCx",
    "Destination": "r3kmLJN5D28dHuH8vZNUZpMC43pEHpaocV",
    "Memos": [
        {
            "Memo": {
                "MemoType": "687474703a2f2f6578616d706c652e636f6d2f6d656d6f2f67656e65726963",
                "MemoData": "72656e74"
            }
        }
    ],
    "Amount": "1"
}

NetworkID Field

The NetworkID field is a protection against "cross-chain" transaction replay attacks, preventing the same transaction from being copied over and executing on a parallel network that it wasn't intended for. For compatibility with existing chains, the NetworkID field must be omitted on any network with a Network ID of 1024 or less, but must be included on any network with a Network ID of 1025 or greater. The following table shows the status and values for various known networks:

Transaction replay attacks are theoretically possible, but require specific conditions on the second network. All of the following must be true:

• The transaction's sender is a funded account on the second network.
• The sender's Sequence number on the second network matches the transaction's Sequence, or the transaction uses a Ticket that's available on the second network.
• Either the transaction does not have a LastLedgerSequence field, or it specifies a value that is higher than the current ledger index on the second ledger.
  • Mainnet generally has a higher ledger index than test networks or sidechains, so it is easier to replay Mainnet transactions on a sidechain or test network than the other way around, when transactions use LastLedgerSequence as intended.
• Either the networks both have IDs of 1024 or less, both networks use the same ID, or the second network does not require the NetworkID field.

Signers Field

The Signers field contains a multi-signature, which has signatures from up to 32 key pairs, that together should authorize the transaction. The Signers list is an array of objects, each with one field, Signer. The Signer field has the following nested fields:

The SigningPubKey must be a key that is associated with the Account address. If the referenced Account is a funded account in the ledger, then the SigningPubKey can be that account's current Regular Key if one is set. It could also be that account's Master Key, unless the lsfDisableMaster flag is enabled. If the referenced Account address is not a funded account in the ledger, then the SigningPubKey must be the master key associated with that address.

Because signature verification is a compute-intensive task, multi-signed transactions cost additional XRP to relay to the network. Each signature included in the multi-signature increases the transaction cost required for the transaction. For example, if the current minimum transaction cost to relay a transaction to the network is 10000 drops, then a multi-signed transaction with 3 entries in the Signers array would need a Fee value of at least 40000 drops to relay.