Running the Metro software: Dependencies: Java 8 or later needs to be installed first. Oracle JVM gives better performance and has been more tested, but OpenJDK is also supported. Using the installer: An IzPack based installation package is provided. Click on the corresponding jar/exe/dmg package, or run "java -jar metro-client.jar" to start the installer. See https://bitbucket.org/JeanLucPicard/nxt/issues/283 for more details about the IzPack installer. After installation, use the shortcuts or desktop icons to start the Metro server. Using the metro-client.zip package: Unpack the metro-client.zip package and open a shell in the resulting metro directory. Execute the run.sh or start.sh script if using Linux or BSD, run.bat if using Windows, or run.command if using Mac. On Unix, the run.sh script must be run from within the installation directory, and uses this directory to search for configuration files, store logs, and for the metro_db blockchain database. The start.sh script can be run from any directory, it starts the java process in the background and uses ~/.metro for configuration files, logs, and the metro_db database. Unlike run.sh, start.sh uses desktop mode, creating a desktop tray icon and opening the JavaFX UI if supported. The initialization takes a few seconds. When it is ready, you should see the message "Metro server 1.x.x started successfully" in the console log. If run in desktop mode, a JavaFX window will open automatically. Otherwise, open a browser, without stopping the java process, and go to http://localhost:7886 , where the Metro UI should now be available. To stop the application, type Ctrl-C inside the console window, or use the stop.sh script if started with start.sh. Warning: It is better to use only latin characters and no spaces in the path to the Metro installation directory, as the use of special characters may result in permissions denied error in the browser, which is a known jetty issue. Customization: There are many configuration parameters that could be changed, but the defaults are set so that normally you can run the program immediately after unpacking, without any additional configuration. To see what options are there, open the conf/metro-default.properties file. All possible settings are listed, with detailed explanation. If you decide to change any setting, do not edit metro-default.properties directly, but create a new conf/metro.properties file and only add to it the properties that need to be different from the default values. You do not need to delete the defaults from metro-default.properties, the settings in metro.properties override those in metro-default.properties. This way, when upgrading the software, you can safely overwrite metro-default.properties with the updated file from the new package, while your customizations remain safe in the metro.properties file. How to contribute? There are many ways to contribute to Metro. Here are some examples: * create pull requests * review pull requests * review existing code * create issues (aka feature ideas, bug reports, documentation etc.) * answer issues Technical details: The Metro software is a client-server application. It consists of a java server process, the one started by the run.sh script, and a javascript user interface run in a browser. A JavaFX UI is also available and starts automatically on supported configurations. To run a node, forge, update the blockchain, interact with peers, only the java process needs to be running, so you could logout and close the browser but keep the java process running. If you want to keep forging, make sure you do not click on "stop forging" when logging out. You can also just close the browser without logging out. The java process communicates with peers on port 57874 tcp by default. If you are behind a router or a firewall and want to have your node accept incoming peer connections, you should setup port forwarding. The server will still work though even if only outgoing connections are allowed, so opening this port is optional. The user interface is available on port 7886. This port also accepts http API requests which other Metro client applications could use. The blockchain is stored on disk using the H2 embedded database, inside the metro_db directory. When upgrading, you should not delete the old metro_db directory, upgrades always include code that can upgrade old database files to the new version whenever needed. But there is no harm if you do delete the metro_db, except that it will take some extra time to download the blockchain from scratch. The default Metro client does not store any wallet-type file on disk. Unlike bitcoin, your password is the only thing you need to get access to your account, and is the only piece of data you need to backup or remember. This also means that anybody can get access to your account with only your password - so make sure it is long and random. A weak password will result in your funds being stolen immediately. The java process logs its activities and error messages to the standard output which you see in the console window, but also to a file metro.log, which gets overwritten at restart. In case of an error, the metro.log file may contain helpful information, so include its contents when submitting a bug report. In addition to the default user interface at http://localhost:7886 , the following urls are available: http://localhost:7886/test - a list of all available http API requests, very useful for client developers and for anyone who wants to execute commands directly using the http interface without going through the browser UI. http://localhost:7886/test?requestType=<specificRequestType> - same as above, but only shows the form for the request type specified. http://localhost:7886/doc - a javadoc documentation for client developers who want to use the Java API directly instead of going through the http interface. Compiling: The source is included in the src subdirectory. To compile it on unix, just run the enclosed compile.sh script. This will compile all java classes and put them under the classes subdirectory, which is already in the classpath used by the run.sh startup script. The compiled class files can optionally be packaged in a metro.jar file using the enclosed jar.sh script, and then metro.jar should be included in the classpath instead of the classes subdirectory.