Offer

[Source]

The Offer ledger entry describes an Offer to exchange currencies in the XRP Ledger's decentralized exchange. (In finance, this is more traditionally known as an order.) An OfferCreate transaction only creates an Offer entry in the ledger when the Offer cannot be fully executed immediately by consuming other Offers already in the ledger.

An Offer can become unfunded through other activities in the network, while remaining in the ledger. When processing transactions, the network automatically removes any unfunded Offers that those transactions come across. (Otherwise, unfunded Offers remain, because only transactions can change the ledger state.)

Example Offer JSON

{
    "Account": "rBqb89MRQJnMPq8wTwEbtz4kvxrEDfcYvt",
    "BookDirectory": "ACC27DE91DBA86FC509069EAF4BC511D73128B780F2E54BF5E07A369E2446000",
    "BookNode": "0000000000000000",
    "Flags": 131072,
    "LedgerEntryType": "Offer",
    "OwnerNode": "0000000000000000",
    "PreviousTxnID": "F0AB71E777B2DA54B86231E19B82554EF1F8211F92ECA473121C655BFC5329BF",
    "PreviousTxnLgrSeq": 14524914,
    "Sequence": 866,
    "TakerGets": {
        "currency": "XAG",
        "issuer": "r9Dr5xwkeLegBeXq6ujinjSBLQzQ1zQGjH",
        "value": "37"
    },
    "TakerPays": "79550000000",
    "index": "96F76F27D8A327FC48753167EC04A46AA0E382E6F57F32FD12274144D00F1797"
}

Offer Fields

In addition to the common fields, Offer entries have the following fields:

Name	JSON Type	Internal Type	Required?	Description
`Account`	String	AccountID	Yes	The address of the account that owns this Offer.
`BookDirectory`	String	Hash256	Yes	The ID of the Offer Directory that links to this Offer.
`BookNode`	String	UInt64	Yes	A hint indicating which page of the offer directory links to this entry, in case the directory consists of multiple pages.
`Expiration`	Number	UInt32	No	Indicates the time after which this Offer is considered unfunded. See Specifying Time for details.
`LedgerEntryType`	String	UInt16	Yes	The value `0x006F`, mapped to the string `Offer`, indicates that this is an Offer entry.
`OwnerNode`	String	UInt64	Yes	A hint indicating which page of the owner directory links to this entry, in case the directory consists of multiple pages.
`PreviousTxnID`	String	Hash256	Yes	The identifying hash of the transaction that most recently modified this entry.
`PreviousTxnLgrSeq`	Number	UInt32	Yes	The index of the ledger that contains the transaction that most recently modified this object.
`Sequence`	Number	UInt32	Yes	The `Sequence` value of the OfferCreate transaction that created this offer. Used in combination with the `Account` to identify this offer.
`TakerPays`	Currency Amount	Amount	Yes	The remaining amount and type of currency requested by the Offer creator.
`TakerGets`	Currency Amount	Amount	Yes	The remaining amount and type of currency being provided by the Offer creator.

Offer Flags

Offer entries can have the following flags combined into the Flags field:

Flag Name	Hex Value	Decimal Value	Corresponding OfferCreate Flag	Description
`lsfPassive`	`0x00010000`	65536	`tfPassive`	The offer was placed as "passive". This has no effect after the offer is placed into the ledger.
`lsfSell`	`0x00020000`	131072	`tfSell`	The offer was placed as a "Sell" offer. This has no effect after the offer is placed in the ledger, because `tfSell` only matters if you get a better rate than you asked for, which can only happen when the offer is initially placed.

Offer Reserve

Offer entries count as one item towards the owner reserve of the account that placed the offer, as long as the entry is in the ledger. Canceling or consuming the offer frees up the reserve. The reserve is also freed up if the offer is removed because it was found unfunded.

Offer ID Format

The ID of an Offer entry is the SHA-512Half of the following values, concatenated in order:

The Offer space key (0x006F)
The AccountID of the account placing the Offer
The Sequence number of the OfferCreate transaction that created the Offer.
If the OfferCreate transaction used a Ticket, use the TicketSequence value instead.