MtGox/API

The MtGox API provides various methods to access different informations from the market, place orders, and more.

Two APIs are available at this point: the HTTP api (available by posting to mtgox.com/code/*) and the websocket API.

Number Formats

In the "old API", currency- and amount-values (price, volume,...) were given as float. These values are likely being deprecated and replaced by fields of the same name with "_int" as suffix. These are fixed-decimal, so you have to move the decimal point yourself (divide). The exponent differs based on the kind of the value.

In order to convert the int to a decimal you can...

kind of field	...divide by	...multiply by
BTC (volume, amount)	1E8 (10,000,000)	0.00000001
USD (price)	1E5 (100,000)	0.00001
JPY (price)	1E3 (1,000)	0.001

Implementation advice: it's probably best to use int or Decimal (if your language/db offers such a type) in your clients. Using float will likely lead to nasty rounding problems.

Legacy API

This API is available in https://mtgox.com/api/0/*, and provides various informations. It also supports making an order, a withdraw, a deposit, etc. There is also a Perl module for interacting with the Legacy API.

Authentication

Authentication is performed by signing each request using HMAC-SHA512. The request must contain an extra value "nonce" which must be an always incrementing numeric value. A reference implementation is provided here:

<?php

function mtgox_query($path, array $req = array()) {
	// API settings
	$key = '';
	$secret = '';

	// generate a nonce as microtime, with as-string handling to avoid problems with 32bits systems
	$mt = explode(' ', microtime());
	$req['nonce'] = $mt[1].substr($mt[0], 2, 6);

	// generate the POST data string
	$post_data = http_build_query($req, '', '&');

	// generate the extra headers
	$headers = array(
		'Rest-Key: '.$key,
		'Rest-Sign: '.base64_encode(hash_hmac('sha512', $post_data, base64_decode($secret), true)),
	);

	// our curl handle (initialize if required)
	static $ch = null;
	if (is_null($ch)) {
		$ch = curl_init();
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
		curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/4.0 (compatible; MtGox PHP client; '.php_uname('s').'; PHP/'.phpversion().')');
	}
	curl_setopt($ch, CURLOPT_URL, 'https://mtgox.com/api/'.$path);
	curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
	curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

	// run the query
	$res = curl_exec($ch);
	if ($res === false) throw new Exception('Could not get reply: '.curl_error($ch));
	$dec = json_decode($res, true);
	if (!$dec) throw new Exception('Invalid data received, please make sure connection is working and requested API exists');
	return $dec;
}

// example 1: get infos about the account, plus the list of rights we have access to
var_dump(mtgox_query('0/info.php'));

// old api (get funds)
var_dump(mtgox_query('0/getFunds.php'));

// trade example
// var_dump(mtgox_query('0/buyBTC.php', array('amount' => 1, 'price' => 15)));

Methods

data/getTrades.php

This allows retrieving all trades which happened in the last 24 hours. The returned data is cached and may not reflect latest activity.

Parameters:

• since: Passing a tid in "since" allows retrieving all trades since that trade. The passed id is may not exist. Ie. to get all trades from the very beginning one would just call https://mtgox.com/code/data/getTrades.php?since=0 . since returns only 100 trades, and you can call the method again by passing the latest trade you have imported in since.

Websocket API

ported on 7/10/2011 from http://forum.bitcoin.org/index.php?topic=5855.0

Connecting

You can connect via: ws://websocket.mtgox.com/mtgox

The WebSocket protocol version used is that described in draft-ietf-hybi-thewebsocketprotocol-00 (aka draft-00).

Channels

The websocket will subscribe you to some channels automatically:

Channel ID	Description
dbf1dee9-4f2e-4a08-8cb7-748919a71b21	trades (each time a trade happens, you get something here)
d5f06780-30a8-4a48-a2f8-7ed181b4a13f	the mtgox ticker (lots of updates, with often the same data)
24e67e0d-1cad-4cc0-9e7a-f8523ef460fe	depth information in realtime (price + amount + type... type=1=Ask, type=2=Bid)

Additionally each user has a "own" channel which streams informations about orders (new order, deleted order, etc) and trades only the user's trades).

Each message is a JSON-encoded object, with at least "op" element. The "op" element contains the operation to be done (for outgoing messages), or the type of message (for incoming messages).

Possible outgoing commands

unsubscribe Stop receiving messages from a channel (parameter "channel")

Incoming Data

Ticker

{
  "channel":"d5f06780-30a8-4a48-a2f8-ed181b4a13f",
  "op":"private",
  "origin":"broadcast",
  "private":"ticker",
  "ticker":{
    "buy":0.9515,
    "high":1,
    "low":0.91,
    "sell":0.9697,
    "vol":34349
  }
}

ticker contains the following:

Name	Value
buy	lowest bid as float
sell	highest ask as float
high	maximum rate since last close as float
low	minimum rate since last close as float
vol	traded volume since last close

Trade

{
  "channel":"dbf1dee9-4f2e-4a08-8cb7-748919a71b21",
  "op":"private",
  "origin":"broadcast",
  "private":"trade",
  "trade":{
    "amount":2.71,
    "amount_int":"271000000",
    "date":1310279340,
    "item":"BTC",
    "price":14.43,
    "price_currency":"USD",
    "price_int":"1443000",
    "tid":"1310279340877902",
    "trade_type":"bid",
    "type":"trade"
  }
}

trade contains the following:

Name	Value
amount	the traded amount in item (BTC), float, deprecated
amount_int	the traded amount * 1E8
date	unix timestamp of trade
item	What was this trade about
price	price per unit, float, deprecated
price_int	price in smallest unit as integer (5 decimals of USD, 3 in case of JPY)
price_currency	currency in which trade was completed
tid	Trade id (big integer, which is in fact trade timestamp in microseconds)
trade_type	Did this trade result from the execution of a bid or a ask?

Depth

Changes to the market depth data are broadcast so an up-to-date market depth can be kept by clients.

{
  "channel":"24e67e0d-1cad-4cc0-9e7a-f8523ef460fe",
  "depth":{
    "currency":"USD",
    "item":"BTC",
    "price":"14.43",
    "price_int":"1443000",
    "type":1,
    "type_str":"ask",
    "volume":"-2.71",
    "volume_int":"-271000000"
  },
  "op":"private",
  "origin":"broadcast",
  "private":"depth"
}

depth contains the following:

Name	Value
currency	the currency affected
item	the item (BTC)
price	price as a float, deprecated
price_int	the price at which volume change happened (5 decimal for USD, 3 for JPY)
type	1=ask, 2=bid. deprecated, use type_str
type_str	type of order at this depth, either "ask" or "bid"
volume	the volume change as float, deprecated
volume_int	volume change * 1E8

Order update (private)

{
  "channel":"(partial key)",
  "op":"private",
  "order_upd":{
    "amount":1000,
    "darkStatus":0,
    "date":1302836027,
    "oid":"(oid)",
    "price":0.9899,"status":1
  },
  "origin":"broadcast",
  "private":"order_upd"
}

order_upd cointains the following:

Name	Value
amount	change in volume of the order
darkStatus
oid	ID of the affected order
price
status