MultiBit Exchange is an open source platform for building exchanges.

A platform that consists of an efficient event-based matching engine with a REST API front-end that allows you to:

• Register multiple currency pairs
• Submit market and limit orders
• Cancel orders
• View the status of your orders
• View market depth
• Stream real-time changes to market depth
• View open orders
• View order history
• View trade history
• Stream real-time trades

MultiBit Exchanges is written by professional developers and is well tested and clean making it easier to understand and extend to:

• Support additional analytics and real-time data streams
• Support additional order types

There is an endless variety of types of exchanges that can be created using MultiBit Exchange. Here are a few ideas:

• An exchange for trading fiat for electronic currencies such as Bitcoin, Litecoin, Dogecoin, and Namecoin.
• An exchange for trading Bitcoin for cell phone minutes, gift cards, gold, etc.
• A precious metal exchange: gold, silver, platinum, etc.
• A traditional currency exchange
• A test platform for experimenting with trading bots, experimental order types, etc.
• An Inter-exchange arbitrage platform

MultiBit Exchange aims to be more that just a functioning exchange, but a well crafted codebase that is:

• Tested
• Neatly structured
• High-throughput / Low-latency by leveraging event sourcing and the LMAX Disruptor pattern.
• Extensible (not necessarily configurable or pluggable, but definitely malleable)
• Strong audit trail. ALL orders, trades, and changes to markets are stored in an audit log.
• Scalable by employing CQRS to keep frequently read data models seperate from core matching engine.

"Clean code always looks like it was written by someone who cares." Michael Feathers

Great software doesn't just happen. It requires a disciplined approach. The following guiding principles are used to develop MultiBit Exchange:

• Focus on the core domain and use of Domain Driven Design principles
• Create tests to guide development - Test Driven Development
• Be disciplined and keep the code well-structured and layered
• Don't re-invent the wheel, but leverage proven technology wherever possible

MultiBit Exchange follows the hexagonal architecture which is also known as the onion architecture. Each prescribes that abstractions should not depend upon details. Details should depend upon abstractions.

This decouples what the system does from how it does it which makes the core domain model cleaner and more focused and therefore easier to understand, test, and extend.

The initial focus is to release a robust Matching Engine. Following that, there are many directions MultiBit Exchange can be taken.

MultiBit Exchange is relatively new, so focus is key, but I have a few ideas about where to go after the first release:

• Accounting & Inter-Broker settlement - include more support for accounting functions
• Decentralization - not sure how yet, but being resistant to shutdown and DDoS attacks is important.
• Enhance Performance - to be able to handle huge volumes without compromising on latency.

Many thanks to all the hard work that was put into the many ideas, libraries, and systems that MultiBit Exchange is built on:

Domain Driven Design lies at the core of MultiBit Exchange. http://skillsmatter.com/expert-profile/home/eric-evans - Thank you Eric Evans.

google-guice - Guice is used for dependency injection throughout. https://code.google.com/p/google-guice/people/list

guava-libraries - Guava is used throughout and makes Java just a little nicer to work with. https://code.google.com/p/guava-libraries/people/list

Dropwizard - Dropwizard serves as the front-end for REST API and web interfaces. http://dropwizard.codahale.com/about/contributors/

LMAX Disruptor - The Disruptor pattern is used to help with speedy production and consumption of events. https://github.com/mikeb01

AXON Framework - The AXON Framework is used to help with CQRS. http://www.axonframework.org/

MongoDB - Much of the persistence is provided by MongoDB. http://www.mongodb.org/

Heroku - Used as a hosting environment during development. https://www.heroku.com/

MongoDB is used as an Event Store and to persist CQRS Read Models. Follow the usual MongoDB installation instructions, such as

$ brew update
$ brew install mongo

Start MongoDB as a background process with

$ mongod &

Then create the following collections through the Mongo CLI

$ mongo
> use mbexchange

From the console you can do the following

$ cd <project root>
$ mvn clean install
$ java -jar target/web-develop-SNAPSHOT.jar server mbexchange-demo.yml

If startup was successful, the first thing you will need to do is create an exchange (a container for currency pairs).

To interact with the REST API use a browser plugin such as POSTMAN which works well with Chrome.

Be sure to include the following header

Content-type: application/json

The format of the JSON document for creating an exchange:

{
  "identifier":"ex"
}

Next, you can navigate to localhost:8080/exchanges/ex/pairs to see a list of currency pairs in the 'ex' exchange. The list should be empty at this point.

To add a currency pair to the exchange POST a JSON document to /exchanges/ex/pairs

Again, be sure to include the following header

Content-type: application/json

The CURRENT format of the JSON document for creating a currency pair:

{
  "baseCurrency": "BaseCCY",
  "counterCurrency": "CounterCCY"
}

Navigate back to localhost:8080/exchanges/ex/pairs to see the newly registered currency pair.

To submit a market order to the exchange POST a JSON document to /exchanges/ex/orders

Again, be sure to include the following header

Content-type: application/json

The format of the JSON document for specifying orders:

{
  "broker":"BrokerIdentifier",
  "side":"Sell",
  "qty":"80.33001",
  "ticker":"BaseCCY/CounterCCY",
  "price":"M"
}

• "broker" can be any string currently.
• "side" is case-insensitive and can be "Buy" or "Sell"
• "qty" is a number between 0 and 10,000,000 with a maximum of 8 decimal places.
• "ticker" must correspond to a previously added currency pair (see above)
• "price" must be "M" for market orders or a number representing limit price for limit orders.

To submit a market order to the exchange POST a JSON document to /exchanges/ex/orders

Again, be sure to include the following header

Content-type: application/json

The format of the JSON document for specifying orders:

{
  "broker":"BrokerIdentifier",
  "side":"Sell",
  "qty":"80.33001",
  "ticker":"BaseCCY/CounterCCY",
  "price":"M"
}

The documentation is a work in progress and can be found at: http://docs.zachscott.apiary.io/

On startup you should see the following:

INFO  [2014-01-25 18:12:40,007] com.yammer.dropwizard.cli.ServerCommand: Starting MultiBitExchangeApiWebService
___  ___      _ _   _______ _ _     _____         _                            
|  \/  |     | | | (_) ___ (_) |   |  ___|       | |                           
| .  . |_   _| | |_ _| |_/ /_| |_  | |____  _____| |__   __ _ _ __   __ _  ___ 
| |\/| | | | | | __| | ___ \ | __| |  __\ \/ / __| '_ \ / _` | '_ \ / _` |/ _ \
| |  | | |_| | | |_| | |_/ / | |_  | |___>  < (__| | | | (_| | | | | (_| |  __/
\_|  |_/\__,_|_|\__|_\____/|_|\__| \____/_/\_\___|_| |_|\__,_|_| |_|\__, |\___|
                                                                     __/ |     
                                                                    |___/


INFO  [2014-01-25 18:12:40,183] com.yammer.dropwizard.config.Environment: 

    GET     /exchanges/{exchangeId}/securities (org.multibit.exchange.infrastructure.adaptor.api.resources.SecuritiesResource)
    GET     /exchanges/{exchangeId}/securities/{ticker}/orderbook (org.multibit.exchange.infrastructure.adaptor.api.resources.SecuritiesResource)
    POST    /exchanges/{exchangeId}/securities (org.multibit.exchange.infrastructure.adaptor.api.resources.SecuritiesResource)
    POST    /exchanges (org.multibit.exchange.infrastructure.adaptor.api.resources.ExchangeResource)
    POST    /exchanges/{exchangeId}/orders (org.multibit.exchange.infrastructure.adaptor.api.resources.ExchangeResource)

INFO  [2014-01-25 18:12:40,183] com.yammer.dropwizard.config.Environment: tasks = 

    POST    /tasks/gc (com.yammer.dropwizard.tasks.GarbageCollectionTask)

http://patorjk.com/software/taag/#p=display&f=Doom&t=MultiBit%20Exchange

Use master for the latest production release. Use develop for the latest release candidate.

If you wish to contribute, please start with develop.

Copyright (c) 2014 Zach Scott, http://zach-scott.com/

This software consists of voluntary contributions made by many individuals (see AUTHORS.txt) For the exact contribution history, see the revision history and logs, available at https://github.com/zscott/MultiBitExchange

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.