AMM

[Source]

An AMM ledger entry describes a single Automated Market Maker (AMM) instance. This is always paired with a special AccountRoot entry. You can create an AMM by sending an AMMCreate transaction.

(Added by the AMM amendment)

Example AMM JSON

{
    "Account": "rBp3UDRuEteeJqp4rEk5kxMe7BGWNYrF9A",
    "Asset": {
      "currency": "XRP"
    },
    "Asset2": {
      "currency": "NEX",
      "issuer": "rQGiPFWhaTDdue1xHX7cVpxGqPQK54zng1"
    },
    "AuctionSlot": {
      "Account": "r3ZGQZw1NCbBp5AEGkMDE9NgNpzw91aofD",
      "Expiration": 778576560,
      "Price": {
        "currency": "03DC324562A8915B7C65E9D31B93D62D02BC491C",
        "issuer": "rBp3UDRuEteeJqp4rEk5kxMe7BGWNYrF9A",
        "value": "0"
      }
    },
    "Flags": 0,
    "LPTokenBalance": {
      "currency": "03DC324562A8915B7C65E9D31B93D62D02BC491C",
      "issuer": "rBp3UDRuEteeJqp4rEk5kxMe7BGWNYrF9A",
      "value": "5509581.299648495"
    },
    "LedgerEntryType": "AMM",
    "OwnerNode": "0",
    "PreviousTxnID": "9E8E9B8FD27391C818525BFF6A29452F7A9888F31622BEF6FC36064D05CF6436",
    "PreviousTxnLgrSeq": 91448830,
    "TradingFee": 1,
    "VoteSlots": [
      {
        "VoteEntry": {
          "Account": "r3ZGQZw1NCbBp5AEGkMDE9NgNpzw91aofD",
          "TradingFee": 1,
          "VoteWeight": 100000
        }
      }
    ],
    "index": "F490627BACE2D0AA744514A640B4999D50E495DD1677550D8B10E2D20FBB15C3"
}

AMM Fields

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

Field	JSON Type	Internal Type	Required?	Description
`Asset`	Object	STIssue	Yes	The definition for one of the two assets this AMM holds. In JSON, this is an object with `currency` and `issuer` fields.
`Asset2`	Object	STIssue	Yes	The definition for the other asset this AMM holds. In JSON, this is an object with `currency` and `issuer` fields.
`Account`	String	AccountID	Yes	The address of the special account that holds this AMM's assets.
`AuctionSlot`	Object	STObject	No	Details of the current owner of the auction slot, as an Auction Slot object.
`LPTokenBalance`	Currency Amount	Amount	Yes	The total outstanding balance of liquidity provider tokens from this AMM instance. The holders of these tokens can vote on the AMM's trading fee in proportion to their holdings, or redeem the tokens for a share of the AMM's assets which grows with the trading fees collected.
`PreviousTxnID`	String	Hash256	No	The identifying hash of the transaction that most recently modified this entry. (Added by the fixPreviousTxnID amendment.)
`PreviousTxnLgrSeq`	Number	UInt32	No	The index of the ledger that contains the transaction that most recently modified this entry. (Added by the fixPreviousTxnID amendment.)
`TradingFee`	Number	UInt16	Yes	The percentage fee to be charged for trades against this AMM instance, in units of 1/100,000. The maximum value is 1000, for a 1% fee.
`VoteSlots`	Array	STArray	No	A list of vote objects, representing votes on the pool's trading fee.

Auction Slot Object

The AuctionSlot field contains an object with the following nested fields:

Field	JSON Type	Internal Type	Required?	Description
`Account`	String - Address	AccountID	Yes	The current owner of this auction slot.
`AuthAccounts`	Array	STArray	No	A list of at most 4 additional accounts that are authorized to trade at the discounted fee for this AMM instance.
`DiscountedFee`	String	UInt32	Yes	The trading fee to be charged to the auction owner, in the same format as `TradingFee`. Normally, this is 1/10 of the normal fee for this AMM.
`Price`	Currency Amount	Amount	Yes	The amount the auction owner paid to win this slot, in LP Tokens.
`Expiration`	String	UInt32	Yes	The time when this slot expires, in seconds since the Ripple Epoch.

VoteEntry Object

The VoteSlots field contains an array of VoteEntry objects with the following fields:

Field	JSON Type	Internal Type	Required?	Description
`Account`	String - Address	AccountID	Yes	The account that cast the vote.
`TradingFee`	Number	UInt16	Yes	The proposed trading fee, in units of 1/100,000; a value of 1 is equivalent to 0.001%. The maximum value is 1000, indicating a 1% fee.
`VoteWeight`	Number	UInt32	Yes	The weight of the vote, in units of 1/100,000. For example, a value of 1234 means this vote counts as 1.234% of the weighted total vote. The weight is determined by the percentage of this AMM's LP Tokens the account owns. The maximum value is 100000.

AMM Reserve

AMM entries do not require a reserve.

AMM Flags

There are no flags defined for AMM entries.

AMM ID Format

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

The AMM space key (0x0041)
The AccountID of the first asset's issuer.
The 160-bit currency code of the first token.
The AccountID of the second asset's issuer.
The 160-bit currency code of the second token.

For XRP, use all 0's for both the token and the issuer.