faast SWAP API

Introduction ¶

Overview ¶

The goal of the faast API is to provide an instant, and secure method to convert from one cryptocurrency to another. To achieve this, a user specifies which currency they possess (deposit currency), and which currency they would like to obtain (withdrawal currency), as well as a wallet address for the currency they would like to obtain.

The faast API then generates a unique deposit wallet address for the “deposit currency”, where the user can send any arbitrary amount of cryptocurrency. Upon noticing any transaction on this deposit address faast will immediately fullfill an order at the current market rate, and send an equivalent amount of “withdrawal currency” to the users specified “wallet address”.

faast never takes custody of users cryptocurrency, and has no user account system. It is designed for instant, safe, and secure conversion in between any arbitrary set of cryptocurrencies.

Basic flow ¶

Order creation:

1. Get a current price/rate (varies in real time with market)

2. Generate an order and deposit address

3. Send cryptocurrency to the deposit address

4. Monitor the status for completion

Fixed pricing vs Variable Pricing ¶

Faast provides two forms of pricing: fixed and variable. When using fixed pricing, an order is created expecting a specific deposit amount in return for a specific withdrawal amount. When using variable pricing, any arbitrary amount can be deposited, and an equivalent withdrawal amount will be calculated using the prevailing exchange rate at the time the deposit is received. This model provides optimal user experience, as well as developer flexibility.

Fixed Pricing ¶

The faast api is inherently asynchronous. There will always be a time lag in-between the time that a swap is created, and a deposit is send for that specific swap. Given the volatility of cryptocurrency markets, even these short delays can cause pricing discrepancies, and as a result, poor user experience.

For this reason, faast provides a “fixed pricing” option when creating a swap. Faast will guarantee the price quoted back in the response assuming the deposit is received before the expiry period. To provide the best experience with fixed pricing, timing is paramount.

How to create a fixed price swap ¶

When calling the /swap endpoint, ensure a deposit_amount is specified, and the generated swap will return a price based on the market depth at the time of the request. The response will contain a price and price_locked_until parameters.

A deposit from the customer must be received before price_locked_until, and match the deposit_amount expected to ensure the price will honored. In the off chance that signing a transaction takes longer than expected, the /swaps/refresh endpoint can be called to refresh the price and re-quote based on an updated market rate.

All transactions are considered “received” when they are detected by a blockchain node on the faast network. Transactions do not need to be “confirmed” or in a “block” to be considered “received”.

Variable pricing ¶

Variable pricing allows for more flexibility, in that users can deposit any amount and receive an equivalent payout based on the prevailing rate at the time the deposit is received.

Given that the API does not know the exact deposit amount, it is impossible to accurately estimate the price of the swap beforehand (due to market depth issues on most cryptocurrencies). For this reason, the specific price of the swap will be quoted when a deposit is received by one of the blockchain nodes on the faast network.

To create a variable price swap, simply omit the deposit_amount when calling the /swap endpoint.

Affiliate Program ¶

Question: Why should I integrate with the faast API and not XYZ API?

Answer: Faast provides the best opportunity for revenue generation as an API integrator.

Earn revenue today by integrating the Faast swap API into your product or service! No sign up is required, and payouts are instant!

Faast allows API integrators to quickly and easily earn revenue by setting a specific percentage of each swap they would like to earn as a commission. Contrary to competitive implementations, the faast affiliate program allows the developer to choose the exact commission they would like to earn.

All earned commission is paid in Bitcoin to the developers specified Bitcoin address. Affiliate payouts are paid in batches after the affiliate commission amount has reached 0.01BTC.

How it works: ¶

When generating a swap on behalf of a customer, simply add the affiliate_margin and affiliate_payment_address field to the request API.

Then, when the customer deposits funds for the swap, the following will happen:

1. The price the customer is quoted will be adjusted down by affiliate_margin
2. An equivalent amount of Bitcoin (deposit_amount * affiliate_margin) will be withheld for an affiliate payout
3. The customer will receive their withdrawal_currency payout
4. After the total affiliate payout for a specific affiliate_payment_address reaches 0.01BTC, it will automatically be sent in a bitcoin transaction.

Affiliate margin ¶

The affiliate margin is a percentage (from 0 to 5) an affiliate would like to charge its customers. Faast prices its swaps based on the prevailing rates on the market, plus an approximate 0.5% fee. Affiliate margins are applied on-top of faast’s native fee.

It is suggested that affiliates make clear to their users the affiliate margin being applied to a swap. The recommended margin is 0.5%, but affiliates are welcome to vary this rate based on business opportunities and application.

Affiliate payment address ¶

Affiliates are recommended to use a single affiliate payment address to simplify accounting. To minimize blockchain bloating, affiliate payouts will be made after the total affiliate commission for a specific address reaches 0.01 BTC.

Affiliate payment addresses must be Bitcoin addresses. If an affiliate prefers to receive their payouts in a different currency, there is a solution! Simply create a variable-rate BTC -> Currency swap using the faast API, and use the BTC deposit address as an affiliate_payment_address. Every time an affiliate payout is sent, it will automatically be converted to the desired payout currency.

Integration Testing ¶

faast provides a staging server that can be used for integration testing. It provides the same API, but with the following differences:

• It uses the TestNet bitcoin and ethereum (ropsten) test network, and thus expects testnet addresses and coins (eg. mqdofsXHpePPGBFXuwwypAqCcXi48Xhb2f)

• ERC20 Tokens are all a single custom faast Token on ropsten address: 0xe72bbed5cf09686c62ed5be8f571a7670c11c468

• testnet coins may or may not be sent to the testnet address provided, depending on how our staging servers are configured

The testing base url is https://testapi.faa.st

Authentication ¶

The majority of the faast APIs have no authentication requirement. The /affiliate APIs are the exception to this, for privacy reasons. Authentication is accomplished through the use of a shared key and secret, used to sign requests. An API key and secret can be obtained through the /affiliate/register API.

Each request must provide the following headers:

• key - API key provided by you

• nonce - an integer value appended to the body when generating the HMAC

• signature - output of the HMAC algorithm

Node.js example:

const requestJSON = JSON.stringify({ ... })
const nonce = String(Date.now())
const signature = crypto
  .createHmac('sha256', 'secret')
  .update(requestJSON + nonce)
  .digest('hex')

request.post({
  url: 'https://testapi.faa.st',
  headers: {
    key: API_KEY,
    nonce: nonce,
    signature: signature
  },
  json: requestJSON
}, function(err, res, body) { ... }

Base URL ¶

Production ¶

The production base URL is https://api.faa.st

Test ¶

The test base URL is https://testapi.faa.st

Swap Requests ¶

Swap statuses ¶

1. awaiting deposit - initial state after a swap has been created

2. received - deposit has been processed

3. awaiting network confirmation - waiting for confirmations of the deposit

4. complete - swap has completed

5. cancelled - no deposit was found

The normal flow for a swap is through the first four statuses in that order. A swap may be cancelled if no valid deposit is seen after a reasonable time period, but note that if a deposit does arrive at the address later on, it will be re-priced and processed.

Content-Type: application/json

{
  "user_id": "my_user_id_992", (optional, user provided ID to be used for historical order lookups)
  "deposit_amount": 0.02, (optional, specify amount for a fixed price swap)
  "deposit_currency": "ETH",
  "withdrawal_address": "0xf9357f4fdef81103ed55296649a7cacf04e80ef3",
  "withdrawal_currency": "BAT",
  "refund_address": "0xf9357f4fdef81103ed55296649a7cacf04e80ef3", (optional, address to send a refund if there are any issues)
  "affiliate_margin": 5, (optional, decimal from 0.0 to 5.0)
  "affiliate_payment_address": "mqdofsXHpePPGBFXuwwypAqCcXi48Xhb2f" (optional, Bitcoin address)
  "fresh_deposit_address": false (optional, return a new deposit address even if this currency pair and withdrawal address combination have already been used)
}

Content-Type: application/json; charset=utf-8

{
  "swap_id": "30711734-e4ee-4ff1-a45b-4020cef8488b",
  "user_id": "my_user_id_992",
  "created_at": "2018-08-17T18:08:59.004Z",
  "deposit_address": "0x94fa1b52E7B6282dad0213e17A8BF7B2538b4b1E",
  "deposit_amount": 0.02,
  "deposit_currency": "ETH",
  "spot_price": 0.03399216,
  "price": 0.035870226,
  "price_locked_at": "2018-08-17T18:08:58.829Z",
  "price_locked_until": "2018-08-17T18:23:58.829Z",
  "withdrawal_address": "0x3d6Bb40C0dDe451812A935163cC57974063b8dA3",
  "withdrawal_currency": "BNB"
}

Content-Type: application/json

Content-Type: application/json; charset=utf-8

{
  "swap_id": "3f1c1a39-de8f-457d-ae2f-11383acd9403",
  "created_at": "2018-08-16T20:04:48.950Z",
  "updated_at": "2018-08-17T22:14:54.620Z",
  "user_id": "my_user_id_992",
  "deposit_address": "0x94fa1b52E7B6282dad0213e17A8BF7B2538b4b1E",
  "deposit_amount": 0.02,
  "deposit_currency": "ETH",
  "spot_price": 0.03375493,
  "price": 0.03731607000000001,
  "price_locked_at": "2018-08-17T22:14:54.619Z",
  "price_locked_until": "2018-08-17T22:29:54.619Z",
  "withdrawal_address": "0x3d6Bb40C0dDe451812A935163cC57974063b8dA3",
  "withdrawal_amount": 0.53596212,
  "withdrawal_currency": "BNB",
  "refund_address": null,
  "status": "awaiting deposit"
}

Content-Type: application/json

Content-Type: application/json; charset=utf-8

{
  "swap_id": "3f1c1a39-de8f-457d-ae2f-11383acd9403",
  "created_at": "2018-08-16T20:04:48.950Z",
  "updated_at": "2018-08-17T22:14:54.620Z",
  "user_id": "my_user_id_992",
  "deposit_address": "0x94fa1b52E7B6282dad0213e17A8BF7B2538b4b1E",
  "deposit_amount": 0.02,
  "deposit_currency": "ETH",
  "spot_price": 0.03375493,
  "price": 0.03731607000000001,
  "price_locked_at": "2018-08-17T22:14:54.619Z",
  "price_locked_until": "2018-08-17T22:29:54.619Z",
  "withdrawal_address": "0x3d6Bb40C0dDe451812A935163cC57974063b8dA3",
  "withdrawal_amount": 0.53596212,
  "withdrawal_currency": "BNB",
  "refund_address": null,
  "status": "awaiting deposit"
}

Content-Type: application/json

{
  "tx_id": "0xasdf..."
}

Content-Type: application/json; charset=utf-8

{
  "swap_id": "3f1c1a39-de8f-457d-ae2f-11383acd9403",
  "created_at": "2018-08-16T20:04:48.950Z",
  "updated_at": "2018-08-17T22:14:54.620Z",
  "user_id": "my_user_id_992",
  "deposit_address": "0x94fa1b52E7B6282dad0213e17A8BF7B2538b4b1E",
  "deposit_tx_id": "0xasdf...",
  "deposit_amount": 0.02,
  "deposit_currency": "ETH",
  "spot_price": 0.03375493,
  "price": 0.03731607000000001,
  "price_locked_at": "2018-08-17T22:14:54.619Z",
  "price_locked_until": "2018-08-17T22:29:54.619Z",
  "withdrawal_address": "0x3d6Bb40C0dDe451812A935163cC57974063b8dA3",
  "withdrawal_amount": 0.53596212,
  "withdrawal_currency": "BNB",
  "refund_address": null,
  "status": "awaiting deposit"
}

Query Requests ¶

Content-Type: application/json

Content-Type: application/json; charset=utf-8

{
  "pair": "BTC_ETH",
  "price": 0.04726611,
  "deposit_amount": 0,
  "minimum_deposit": 0.00028219
}

Content-Type: application/json

Content-Type: application/json; charset=utf-8

[
  {
    "name": "Bitcoin",
    "symbol": "BTC",
    "walletUrl": "https://copay.io",
    "deposit": true,
    "receive": true,
    "infoUrl": "https://bitcoin.org",
    "decimals": 8,
    "cmcID": "bitcoin",
    "iconUrl": "https://api.faa.st/api/v1/public/static/img/coins/icon_BTC.png"
  },
  {
    "name": "Ethereum",
    "symbol": "ETH",
    "walletUrl": "https://faa.st",
    "deposit": true,
    "receive": true,
    "infoUrl": "https://ethereum.org",
    "decimals": 18,
    "cmcID": "ethereum",
    "iconUrl": "https://api.faa.st/api/v1/public/static/img/coins/icon_ETH.png"
  },
  {
    "name": "Augur",
    "validate": "ETH",
    "symbol": "REP",
    "walletUrl": "https://faa.st",
    "deposit": true,
    "receive": true,
    "ERC20": true,
    "infoUrl": "https://etherscan.io/token/0x1985365e9f78359a9B6AD760e32412f4a445E862",
    "contractAddress": "0x1985365e9f78359a9B6AD760e32412f4a445E862",
    "decimals": 18,
    "cmcID": "augur",
    "iconUrl": "https://api.faa.st/api/v1/public/static/img/coins/icon_REP.png"
  }, ...
]

Content-Type: application/json

Content-Type: application/json; charset=utf-8

{
  "name": "Bitcoin",
  "symbol": "BTC",
  "walletUrl": "https://copay.io",
  "deposit": true,
  "receive": true,
  "infoUrl": "https://bitcoin.org",
  "decimals": 8,
  "cmcID": "bitcoin",
  "iconUrl": "https://api.faa.st/api/v1/public/static/img/coins/icon_BTC.png"
}

Content-Type: application/json

Content-Type: application/json; charset=utf-8

{
  "minimum_deposits": {
    "BAT": 18.67064974,
    "BTC": 0.00040536,
    "ETH": 0.01457336,
    "TUSD": 3.30425588,
    "ZRX": 4.60574797
  },
  "maximum_deposits": {
    "BAT": 701821,
    "BTC": 100,
    "ETH": 1421,
    "TUSD": 80881,
    "ZRX": 132395
  },
  "maximum_withdrawals": {
    "BAT": 225742,
    "BTC": 100,
    "ETH": 1792,
    "TUSD": 82944,
    "ZRX": 58200
  },
  "prices": {
    "BAT": {
      "BTC": 37528.00597461,
      "ETH": 1288.22461165,
      "TUSD": 5.71288835,
      "ZRX": 4.10593914
    },
    "BTC": {
      "BAT": 0.000027,
      "ETH": 0.03449866,
      "TUSD": 0.00015299,
      "ZRX": 0.00010996
    },
    "ETH": {
      "BAT": 0.00078709,
      "BTC": 29.29245176,
      "ETH": 13018.36041509,
      "TUSD": 57.73250944,
      "ZRX": 41.49322641
    },
    "TUSD": {
      "BAT": 0.17845856,
      "BTC": 6641.55432197,
      "ETH": 227.98476804,
      "ZRX": 0.72665246
    },
    "ZRX": {
      "BAT": 0.24875046,
      "BTC": 9257.55342667,
      "ETH": 317.78422163,
      "TUSD": 1.40927736
    }
  }
}

Content-Type: application/json

Content-Type: application/json; charset=utf-8

{
  "total": 1,
  "orders": [
    {
      "swap_id": "ab0d3433-723a-4b6e-8c1c-a487103c1eb1",
      "user_id": "my_user_id_992",
      "created_at": "2018-08-17T16:25:47.659Z",
      "updated_at": "2018-08-17T17:01:14.130Z",
      "deposit_address": "0x94fa1b52E7B6282dad0213e17A8BF7B2538b4b1E",
      "deposit_amount": 0.02,
      "deposit_currency": "ETH",
      "spot_price": 0.03435726,
      "price": 0.037981955000000005,
      "price_locked_at": "2018-08-17T16:25:47.650Z",
      "price_locked_until": "2018-08-17T16:40:47.650Z",
      "withdrawal_address": "0x3d6Bb40C0dDe451812A935163cC57974063b8dA3",
      "withdrawal_currency": "BNB",
      "withdrawal_amount": 1.16252102,
      "status": "complete",
      "amount_deposited": 0.04,
      "amount_withdrawn": 1.16252102,
      "transaction_id": "0x849cfa8edde231c50cab8a4a3a2a1c8530797c870ef28b189cd5b58d63eb2ac2"
    }
  ]
}

Affiliate ¶

Content-Type: application/json

{
  "key": "my_api_key", (user provided key)
  "affiliate_payment_address": "mqdofsXHpePPGBFXuwwypAqCcXi48Xhb2f" (Bitcoin address for payouts)
  "contact_email": "[email protected]" (email address for support outreach)
}

Content-Type: application/json; charset=utf-8

{
  "key": "my_api_key",
  "secret": "2f03aa6c02061447560b9880bc4924ea2435",
  "affiliate_payment_address": "mqdofsXHpePPGBFXuwwypAqCcXi48Xhb2f",
  "contact_email": "[email protected]"
}

Content-Type: application/json

Content-Type: application/json; charset=utf-8

{
  "count": 2,
  "limit": 10,
  "cursor": "asdf...",
  "records": [
    {
      "created": "2018-10-02T17:23:07.632Z",
      "updated": "2018-10-02T17:23:51.541Z",
      "address": "msDLdZWQd7HJKGqQyw2TDiCGWjTqjYG2dh",
      "amount": 0.07790316,
      "currency": "BTC",
      "status": "paid",
      "tx_hash": "b6bea2f494b312d004d646a9ecc79c37359ffa9b04366ba6598079c830e49df0"
    },
    {
      "created": "2018-09-28T20:27:51.744Z",
      "updated": "2018-09-28T20:28:11.894Z",
      "address": "msDLdZWQd7HJKGqQyw2TDiCGWjTqjYG2dh",
      "amount": 0.07790316,
      "currency": "BTC",
      "status": "pending"
    }
  ]
}

Content-Type: application/json

Content-Type: application/json; charset=utf-8

{
  "date": "2018-10-23T16:03:46.743Z",
  "address": "mqdofsXHpePPGBFXuwwypAqCcXi48Xhb2f",
  "totals": {
    "swaps_created": 34,
    "swaps_completed": 16,
    "value_usd": 0,
    "value_btc": 0,
    "affiliate_payouts_usd": 0,
    "affiliate_payouts_btc": 0,
    "by_currency": {
      "BNB": {
        "swaps_completed": 8,
        "value_currency": 0,
        "value_usd": 0,
        "value_btc": 0,
        "affiliate_payouts_usd": 0,
        "affiliate_payouts_btc": 0,
        "deposits": {
          "swaps_completed": 4,
          "value_currency": 0,
          "value_usd": 0,
          "value_btc": 0,
          "affiliate_payouts_usd": 0,
          "affiliate_payouts_btc": 0
        },
        "withdrawals": {
          "swaps_completed": 4,
          "value_currency": 0,
          "value_usd": 0,
          "value_btc": 0,
          "affiliate_payouts_usd": 0,
          "affiliate_payouts_btc": 0
        }
      },
      "ETH": {
        "swaps_completed": 8,
        "value_currency": 0,
        "value_usd": 0,
        "value_btc": 0,
        "affiliate_payouts_usd": 0,
        "affiliate_payouts_btc": 0,
        "deposits": {
          "swaps_completed": 4,
          "value_currency": 0,
          "value_usd": 0,
          "value_btc": 0,
          "affiliate_payouts_usd": 0,
          "affiliate_payouts_btc": 0
        },
        "withdrawals": {
          "swaps_completed": 4,
          "value_currency": 0,
          "value_usd": 0,
          "value_btc": 0,
          "affiliate_payouts_usd": 0,
          "affiliate_payouts_btc": 0
        }
      }
    }
  },
  "terms": "https://faa.st/terms"
}

History ¶

Version 0.1: ¶

• Add currently supported APIs

• GET rate

• GET txStat

• POST shift

• Add initial list of supported Deposit and withdrawal Currencies

Version 0.2: ¶

• Removed list of supported currencies from doc, use v1 currencies API to get currency list

• Removed /shift

• Removed /txStat

• Add initial v2 APIs

• GET price

• GET swaps

• POST swap

• POST swap/refresh

Version 0.2.1: ¶

• Fixed lack of URI parameter in refresh API

Version 0.3.0: ¶

• added GET swap

Version 0.4.0: ¶

• added GET /affiliate/:address/payouts

Version 0.5.0: ¶

• added GET /price/all

• added GET /affiliate/:address/stats

• fixed affiliate payouts documentation to include cursor

Version 0.6.0: ¶

• added POST /swap/deposit

Version 0.7.0: ¶

• /affiliate/stats and /affiliate/payouts now require authentication

• added POST /affiliate/register for obtaining api keys

Version 0.8.0: ¶

• /affiliate/stats response format has changed

• /affiliate/stats can be restricted by start/end date

Version 0.9.0: ¶

• /swap: added new fresh_deposit_address parameter

• added description of swap status values

Version 0.10.0: ¶

• removed affiliate_payment_address and affiliate_margin from swap responses

Version 0.11.0: ¶

• added maximum_deposits and maximum_withdrawals to price/all API