Streamtools is a graphical toolkit for dealing with streams of data. Streamtools makes it easy to explore, analyse, modify and learn from streams of data.

Quick links from our wiki:

• how to use the GUI
• block documentation
• how to use the API
• how to compile

• download st from the streamtools releases page
• run st locally or on server
• in a browser, visit port 7070 of the machine you ran st on.

Mostly, you'll interact with streamtools in the browser. A server program, called st runs on a computer somewhere that serves up the streamtools webpage. Either it will be on your local machine, or you can put it on a remote machine somewhere - we often run it on a virtual computer in Amazon's cloud so we can leave streamtools running for long periods of time. To begin with, though, we'll assume that you're running streamtools locally, on a machine you can touch. We're also going to assume you're running OSX or Linux - if you're a Windows user you will need to compile the code yourself.

So, first of all, you need to download the streamtools server. It's just a single file, and you can find the latest release on github. Download this file, and move it to your home directory. Now, open a terminal and run the streamtools server by typing ~/st. You should see streamtools start up, telling you it's running on port 7070.

Now, open a browser window and point it at localhost:7070. You should see a (nearly) blank page. At the bottom you should see a status bar that says client: connected to Streamtools followed by a version number. Congratulations! You're in.

As a "Hello World", try double-clicking anywhere on the page above the status bar, type fromhttpstream and hit enter. This will bring up your first block. Double-click on the block and enter http://developer.usa.gov/1usagov in the Endpoint text-box. Hit the update button. Now double-click on the page and make a tolog block. Finally, connect the two blocks together by first clicking on the fromhttpstream block's OUT route (a litle black square on the bottom of the block) to the tolog block's IN route (which is the little black square on the top of the block). Click on the status bar and, after a moment, you should start to see JSON scroll through the log - these are live clicks on the US government short links! Click anywhere on the log to make it go away again.

The streamtools server is completely contained in a single binary called st. It has a number of options:

• --port=7070 - specify a port number to run on. Default is 7070.
• --domain=localhost - if you're accessing streamtools through a URL that's not localhost, you need to specify it using this option.

Streamtools' basic paradigm is straightforward: data flows from blocks through connections to other blocks. A block perfoms some operation on each message it recieves, and that operation is defined by the block's type. Each block has zero or more rules which define that block's behaviour. Each block has a set of named routes that can recieve data, emit data, or respond to queries.

A block's rule can be set directly by double clicking on a block and typing in the rule manually. Alternatively, a block's rule can be set by sending an appropriately formed message to the block's rule route.

You can connect blocks together, via their routes, using connections. You can connect to any inbound route, and so data flowing through streamtools can be used to set the rules of the blocks in the running pattern.

We call a collection of connected blocks a pattern, and it is possible to export and import whole patterns from a running instance of streamtools. Together, these 5 concepts: blocks, rules, connections, routes and patterns form the basic vocabulary we use to talk about streamtools.

• For background on responsive programming tools see Bret Victor's learnable programming.