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Protocols

AirSwap trading technology is fully decentralized, powered by smart contracts that enable counterparty discovery and atomic swaps. AirSwap protocols communicate prices off-chain and settle on-chain. Peers take the form of individuals trading manually or software trading in an automated way, in which case market makers run servers that implement the following protocols.

For information on finding counter-parties, see Discovery.

Discovery

AirSwap Discovery protocol is used to determine the trading protocols and tokens supported by peers.

getProtocols

Peers may call getProtocols to determine protocols supported by a peer. Protocols are identified by interfaceId and configuration params include the chainId, swapContractAddress, and walletAddress that the peer intends to use.

getProtocols(): [
  {
    interfaceId: string,
    params: {
      chainId: string,
      swapContractAddress: string,
      walletAddress: string,
    }
  }, ...
]

setProtocols

When connected via WebSocket, the server may send a setProtocols notification to the client to indicate the protocols it supports. Protocols are identified by interfaceId and configuration params include the chainId, swapContractAddress, and walletAddress the server intends to use.

setProtocols([
  {
    interfaceId: string,
    params: {
      chainId: string,
      swapContractAddress: string,
      walletAddress: string,
    }
  }, ...
])

getTokens

Peers may call getTokens to determine tokens supported by another peer, whether connected via HTTPS or WebSocket. The return value is an array of tokens identified by the token contract address.

getTokens(): [ tokenContractAddress, ... ]

setTokens

When connected via WebSocket, the server may send a setTokens notification to indicate the tokens it supports.

setTokens([ tokenContractAddress, ... ])

RequestForQuoteERC20

AirSwap RequestForQuoteERC20 is a client-server protocol used by market makers running servers from which clients request ERC20 orders via HTTP or WebSocket. In RFQ, the server is the signer (i.e. signerAmount, signerToken) and the client is the sender (i.e. senderAmount, senderToken).

getSignerSideOrderERC20

Given a senderAmount the server returns a signed OrderERC20 including the signerAmount. The client is selling to the server. Client may optionally request a minimum expiry in seconds. Returns an order.

getSignerSideOrderERC20(
  chainId: string,      // ID of the chain intended for use
  swapContract: string, // Swap contract intended for use
  signerToken: string,  // Token the signer would transfer
  senderAmount: string, // Amount the sender would transfer
  senderToken: string,  // Token the sender would transfer
  senderWallet: string, // Wallet of the sender
  minExpiry?: string,   // Minimum required expiry
  proxyingFor?: string, // Ultimate counterparty
): OrderERC20

getSenderSideOrderERC20

Given a signerAmount the server returns a signed OrderERC20 with a senderAmount. The client is buying from the server. Client may optionally request a minimum expiry in seconds. Returns an order.

getSenderSideOrderERC20(
  chainId: string,      // ID of the chain intended for use
  swapContract: string, // Swap contract intended for use
  signerToken: string,  // Token the signer would transfer
  signerAmount: string, // Amount the signer would transfer
  senderToken: string,  // Token the sender would transfer
  senderWallet: string, // Wallet of the sender
  minExpiry?: string,   // Minimum required expiry
  proxyingFor?: string, // Ultimate counterparty
): OrderERC20

getPricingERC20

Client may request soft pricing for a list of token pairs. Client may optionally request a minimum expiry in seconds to be factored into pricing. Returns current formula or levels for each pair.

getPricingERC20(
  pairs: [
    {
      baseToken: string,
      quoteToken: string
    }, ...
  ],
  minExpiry?: string,
): [
  {
    baseToken: string,
    quoteToken: string,
    minimum: string,
    bid: Levels | Formula,
    ask: Levels | Formula
  }, ...
]

Client may also request pricing for all available pairs.

getAllPricingERC20(
  minExpiry?: string,
): [
  {
    baseToken: string,
    quoteToken: string,
    minimum: string,
    bid: Levels | Formula,
    ask: Levels | Formula
  }, ...
]

Example

To find counterparties, see Discovery. With server URLs in hand, clients may call getSignerSideOrderERC20 or getSenderSideOrderERC20 as JSON-RPC requests on servers that support RequestForQuoteERC20.

Client Request

POST / HTTP/1.1
Content-Length: ...
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 123,
  "method": "getSignerSideOrderERC20",
  "params": {
    "chainId": "1",
    "swapContract": "0xd82FA167727a4dc6D6F55830A2c47aBbB4b3a0F8",
    "signerToken": "0xdac17f958d2ee523a2206206994597c13d831ec7",
    "senderWallet": "0xed669F5fe2A37Ef204DB178c7a982717B9f03Ec2",
    "senderToken": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
    "senderAmount": "1000000000000000000",
  }
}

Requests can also be made using curl or wget for debugging.

curl -H 'Content-Type: application/json' \
     -d '{"jsonrpc":"2.0","id":"123","method":"getSignerSideOrderERC20","params":{"chainId":"1","swapContract":"0xd82FA167727a4dc6D6F55830A2c47aBbB4b3a0F8","signerToken":"0xdac17f958d2ee523a2206206994597c13d831ec7","senderWallet":"0xed669F5fe2A37Ef204DB178c7a982717B9f03Ec2","senderToken":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2","senderAmount":"1000000000000000000"}}' \
     http://localhost:3000/

Server Response

See the signatures page for details on signing an OrderERC20.

HTTP/1.1 200 OK
Access-Control-Allow-Origin: *
Access-Control-Allow-Headers: *
Access-Control-Allow-Methods: POST, OPTIONS
Content-Length: ...
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 123,
  "result": {
    "nonce": "99",
    "expiry": "1566941284",
    "signerWallet": "0x73BCEb1Cd57C711feaC4224D062b0F6ff338501f",
    "signerToken": "0xdac17f958d2ee523a2206206994597c13d831ec7",
    "signerAmount": "100000000",
    "senderToken": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
    "senderAmount": "1000000000000000000",
    "v": "28",
    "r": "0x67e0723b0afd357d4f28523bf633dfee16e0eab2f3cbcf8ce1afd32a035d2764",
    "s": "0x1b71e6e633b3334fc88faf4ec0ca1b7611883bc0de4df7024abec07af78b97c3"
  }
}

Client Settlement

With an OrderERC20 in hand, the client sends an Ethereum transaction to the SwapERC20 contract. The swapLight function is gas efficient, whereas the swap function provides protocol fee rebates to staked AST holders. Either function can settle a correctly signed OrderERC20. A successful swap emits a SwapERC20 event.

  function swapLight(
    uint256 nonce,
    uint256 expiry,
    address signerWallet,
    address signerToken,
    uint256 signerAmount,
    address senderToken,
    uint256 senderAmount,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;
  event SwapERC20(
    uint256 indexed nonce,
    address indexed signerWallet,
    address signerToken,
    uint256 signerAmount,
    uint256 protocolFee,
    address indexed senderWallet,
    address senderToken,
    uint256 senderAmount
  );

The server or client may subscribe to a filter for a SwapERC20 event with the order nonce to track fills.

LastLookERC20

AirSwap LastLookERC20 is used by servers to stream quotes to clients. Clients periodically send signed OrderERC20s to the server, which then has the "last look" and option to send it to the EVM for settlement. In last-look, the client is the signer (e.g. signerAmount, signerToken) and the server is the sender (e.g. senderAmount, senderToken).

subscribePricingERC20

Client subscribes to pricing updates for a list of token pairs. Returns current formula or levels for each pair.

subscribePricingERC20([
  {
    baseToken: string,
    quoteToken: string
  }, ...
]): [
  {
    baseToken: string,
    quoteToken: string,
    minimum: string,
    bid: Levels | Formula,
    ask: Levels | Formula
  }, ...
]

Client may also subscribe to pricing updates for all available pairs. Returns current formula or levels for each pair.

subscribeAllPricingERC20(): [
  {
    baseToken: string,
    quoteToken: string,
    minimum: string,
    bid: Levels | Formula,
    ask: Levels | Formula
  }, ...
]

unsubscribePricingERC20

Client unsubscribes from pricing updates for a list of token pairs. Returns a boolean.

unsubscribePricingERC20([
  {
    baseToken: string,
    quoteToken: string
  }, ...
]): boolean

Client may also unsubscribe from all subscriptions. Returns a boolean.

unsubscribeAllPricingERC20(): boolean

setPricingERC20

Server updates pricing for one or more token pairs. Returns a boolean.

setPricingERC20(
  pricing: [
    {
      baseToken: string,
      quoteToken: string,
      minimum: string,
      bid: Levels | Formula,
      ask: Levels | Formula
    }, ...
  ]
)

considerOrderERC20

Client provides a priced OrderERC20 to the server. Returns boolean true if accepted by the server.

considerOrderERC20(
  nonce: string,
  expiry: string,
  signerWallet: string,
  signerToken: string,
  signerAmount: string,
  senderToken: string,
  senderAmount: string,
  v: string,
  r: string,
  s: string
): boolean

Example

To find counterparties, see Discovery. With WebSocket server URLs in hand (i.e. the URL schema is wss), clients connect to each and calls methods as JSON-RPC over WebSocket.

WebSocket

Upon connection, the server calls setProtocols on the client.

{
  "jsonrpc": "2.0",
  "method": "setProtocols",
  "id": 123,
  "params": [
    [
      {
        "interfaceId": "0x2ca4c820",
        "params": {
          "chainId": "1",
          "swapContractAddress": "0xd82FA167727a4dc6D6F55830A2c47aBbB4b3a0F8",
          "walletAddress": "0x73BCEb1Cd57C711feaC4224D062b0F6ff338501f"
        }
      }
    ]
  ]
}

The client may then subscribe to pricing updates.

{
  "jsonrpc": "2.0",
  "method": "subscribeAllPricingERC20",
  "id": 123,
  "params": []
}

The server then continuously updates the client with new pricing.

{
  "jsonrpc": "2.0",
  "method": "setPricingERC20",
  "id": 123,
  "params": [
    [
      {
        "baseToken": "0xdac17f958d2ee523a2206206994597c13d831ec7",
        "quoteToken": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
        "bid": [
          ["100", "0.00053"],
          ["1000", "0.00061"],
          ["10000", "0.0007"]
        ],
        "ask": [
          ["100", "0.00055"],
          ["1000", "0.00067"],
          ["10000", "0.0008"]
        ]
      }
    ]
  ]
}

The client may send an OrderERC20 to the server to consider a swap.

{
  "jsonrpc": "2.0",
  "id": 123,
  "method": "considerOrderERC20",
  "params": {
    "nonce": "1",
    "expiry": "1629117312",
    "signerWallet": "0x0...",
    "signerToken": "0xdac17f958d2ee523a2206206994597c13d831ec7",
    "signerAmount": "1000000000",
    "senderToken": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
    "senderAmount": "530000000000000000",
    "v": "28",
    "r": "0x0...",
    "s": "0x0..."
  }
}

With an OrderERC20 in hand, the server sends an Ethereum transaction to the SwapERC20 contract. The swapLight function is gas efficient, whereas the swap function provides protocol fee rebates to staked AST holders. Either function can settle a correctly signed OrderERC20. A successful swap emits a SwapERC20 event.

The client may subscribe to a filter for a SwapERC20 event with the nonce they provided to the server to track fills.

Indexing

AirSwap Indexing is used by peers to store and fetch orders on other peers.

addOrder

Peers may call addOrder to add an order to another peer.

addOrder(
  order: FullOrder,
  tags: string[]
): boolean

getOrders

Peers may call getOrders to query for orders indexed by another peer.

getOrders(
  filter: OrderFilter,
  offset: number,
  limit: number,
  by = Indexes.EXPIRY,
  direction = Direction.ASC
): (
  orders: FullOrder[],
  offset: number,
  total: number
)

getTags

Peers may call getTags to get all available tags for a token.

getTags(
  token: address
): string[]

Where OrderFilter, Indexes, and Direction can be found here.

IndexingERC20

AirSwap Indexing is used by peers to store and fetch ERC20 orders on other peers.

addOrderERC20

Peers may call addOrderERC20 to add an order to another peer.

addOrderERC20(
  order: FullOrderERC20,
  tags: string[]
): boolean

getOrdersERC20

Peers may call getOrdersERC20 to query for orders indexed by another peer.

getOrdersERC20(
  filter: OrderFilter,
  offset: number,
  limit: number,
  by = Indexes.EXPIRY,
  direction = Direction.ASC
): (
  orders: FullOrderERC20[],
  offset: number,
  total: number
)

Where OrderFilter, Indexes, and Direction can be found here.

getTags

Peers may call getTags to get all available tags for a token.

getTags(
  token: address
): string[]

Pricing Formats

Server pricing can be communicated either by levels or a formula. All input and output values for pricing are in base units rather than atomic units. When generating orders, all values must be converted to atomic units.

Levels

A server may provide "levels" to determine its pricing for various tokens and amounts. Each level is a tuple of amount and price at that level. Amounts and minimums are all in baseToken. Each level indicates price “up to” the specified amount and therefore the last level is the maximum.

;[
  {
    baseToken: '0xdac17f958d2ee523a2206206994597c13d831ec7',
    quoteToken: '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2',
    bid: [
      ['100', '0.00053'],
      ['1000', '0.00061'],
      ['10000', '0.0007'],
    ],
    ask: [
      ['100', '0.00055'],
      ['1000', '0.00067'],
      ['10000', '0.0008'],
    ],
  },
  {
    baseToken: '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2',
    quoteToken: '0xdac17f958d2ee523a2206206994597c13d831ec7',
    bid: [
      ['0.5', '2000'],
      ['1', '2010'],
      ['10', '2050'],
    ],
    ask: [
      ['0.5', '2001'],
      ['1', '2015'],
      ['10', '2060'],
    ],
  },
]

Examples

Client wants to swap 1000 USDT into WETH. Client looks up baseToken USDT and quoteToken WETH and uses the bid levels above. The first 100 would be multiplied by 0.00053 and second 900 would be multiplied by 0.00061 for a total of 0.602 WETH.

Client wants to swap 1 WETH into USDT. Client looks up baseToken WETH and quoteToken USDT and uses the bid levels above. The first 0.5 would be multiplied by 2000 and second 0.5 would be multiplied by 2010 for a total of 2005 USDT.

Client wants to swap WETH into 1000 USDT. Client looks up baseToken USDT and quoteToken WETH and uses the ask levels above. The first 100 would be multiplied by 0.00055 and second 900 would be multiplied by 0.00067 for a total of 0.658 WETH.

Client wants to swap USDT into 1 WETH. Client looks up baseToken WETH and quoteToken USDT and uses the ask levels above. The first 0.5 would be multiplied by 2001 and second 0.5 would be multiplied by 2015 for a total WETH amount of 2008 USDT.

Formula

The server can specify formulas to use for pricing. Each formula is an expression with operations including addition, subtraction, multiplication, and division, where x is provided by the client.

;[
  {
    baseToken: '0xdac17f958d2ee523a2206206994597c13d831ec7',
    quoteToken: '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2',
    bid: 'x*0.00053',
    ask: 'x*0.00055',
  },
  {
    baseToken: '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2',
    quoteToken: '0xdac17f958d2ee523a2206206994597c13d831ec7',
    bid: 'x*2000',
    ask: 'x*2001',
  },
]

Examples

Client wants to swap 1000 USDT into WETH. Client looks up baseToken USDT and quoteToken WETH and uses the bid levels above. 1000 is multiplied by 0.00053 for a total of 0.53 WETH.

Client wants to swap 1 WETH into USDT. Client looks up baseToken WETH and quoteToken USDT and uses the bid levels above. 1 is multiplied by 2000 for a total of 2000 WETH.

Client wants to swap WETH into 1000 USDT. Client looks up baseToken USDT and quoteToken WETH and uses the ask levels above. 1000 is multiplied by 0.00055 for a total of 0.55 WETH.

Client wants to swap USDT into 1 WETH. Client looks up baseToken WETH and quoteToken USDT and uses the ask levels above. 1 is multiplied by 2001 for a total of 2001 WETH.

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