0.0.4-beta.30 • Public • Published


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plasma-client is a lightweight plasma chain client that allows you to make transactions on a plasma chain. You can think of it like the equivalent of parity or geth for Ethereum.

Just looking to make your first transaction? Skip ahead to the Getting Started section!


Welcome! If you're looking to contribute to plasma-client, you're in the right place.

Contributing Guide and CoC

Plasma Group follows a Contributing Guide and Code of Conduct adapted slightly from the Contributor Covenant. All contributors are expected to read through this guide. We're here to cultivate a welcoming and inclusive contributing environment, and every new contributor needs to do their part to uphold our community standards.

Contributor Setup


plasma-client has a few requirements:

  • git
  • Node.js

You'll find detailed instructions on installing these requirements in our Getting Started section.


plasma-client makes use of several npm packages.

Install all required packages with:

npm install

Running Tests

plasma-client makes use of a combination of Mocha (a testing framework) and Chai (an assertion library) for testing.

Run all tests with:

npm test

Contributors: remember to run tests before submitting a pull request! Code with passing tests makes life easier for everyone and means your contribution can get pulled into this project faster. :-)

Getting Started

Running plasma-client is pretty simple. Here we'll take you through the steps to get started with plasma-client and make your first plasma transactions!

Running a Terminal

Before you keep going, it's probably good to become familiar with using the terminal on your computer. Here are some resources for getting started:

Installing Git

git is an open source version control system. You don't really need to know how it works, but you will need it in order to install plasma-client.


Atlassian has a good tutorial on installing git on Windows. It's basically just installing an .exe and running a setup wizard.


Installing git on a Mac is pretty easy. You basically just need to type git into your terminal. If you have git installed, you'll see a bunch of output. Otherwise, you'll get a pop-up asking you to install some command-line tools (including git).


Installing git on Linux is also pretty easy. However, the exact install process depends on your distribution. Here's a guide for installing on some popular distributions.

Installing Node.js

Most of the Plasma Group apps are built in JavaScript and make use of a tool called Node.js. In order to run our tools, including plasma-client, you'll need to make sure that you’ve got Node.js installed.

Here's a list of ways to install Node.js on different operating systems:


If you're on a windows computer, you can download the latest Long-term Support (LTS) version of Node.js here. You'll just need to install the .msi file that Node.js provides and restart your computer.


You have some options if you want to install Node.js on a Mac. The simplest way is to download the .pkg file from the Node.js downloads page. Once you've installed the .pkg file, run this command on your terminal to make sure everything is working properly:

node -v

If everything is working, you should see a version number pop up that looks something like this:


Note: If you've already installed Node.js with the above steps, you can skip this section!

You can also install Node.js using Homebrew. First, make sure Homebrew is up to date:

brew update

Now just install Node.js:

brew install node


There are different ways to install Node.js depending on your Linux distribution. Here's an article that goes through installing Node.js on different distributions.

Installing plasma-client

Once you've got Node.js installed, installing plasma-client is as simple as running this command in your terminal:

npm install -g plasma-client 

You might get an error that looks like this:

npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
npm ERR!  { [Error: EACCES: permission denied, access '/usr/local/lib/node_modules']
npm ERR!   stack:
npm ERR!    "Error: EACCES: permission denied, access '/usr/local/lib/node_modules'",
npm ERR!   errno: -13,
npm ERR!   code: 'EACCES',
npm ERR!   syscall: 'access',
npm ERR!   path: '/usr/local/lib/node_modules' }

Don't worry, you're not doing anything wrong! This has to do with how Node.js installs things -- sometimes it tries to install stuff in places it doesn't have permission to install. There are a few ways to get around this problem. First, try following these instructions, then restart your terminal and try installing plasma-client again. If you can't get that to work, you can also try installing as root:

sudo npm install -g plasma-client

Once you get plasma-client install, you'll have access to two commands from your terminal, plasma-client and plasma-cli. plasma-client is the actual software that allows you to make transactions and see your balances. plasma-cli is a command-line interface that talks to plasma-client and makes it easy to quickly start sending transactions using your terminal.

Launching the Client

Now that you've installed plasma-client, it’s easy to connect to a plasma chain! If you’re looking to quickly get started, you just run the following command in your terminal:


This will connect you to the Plasma Group plasma chain by default. You can also connect to another plasma chain by running this command instead:

plasma-client —-operator

If everything goes to plan, you should see something like this:

Plasma Client v0.0.4-beta.4

Available Accounts

Client Information

Listening on: http://localhost:9898

  service:operator Successfully connected to operator +0ms

That means your client is running and ready to start sending and receiving transactions. Congrats!

Common Errors

The Plasma Group plasma chain currently uses a single party, called an operator, to aggregate transactions into blocks. The cool thing about plasma is that your funds are always safe, even if the operator tries to steal them! However, this does mean that we’re susceptible to the occasional outages that any software service will have. As a result, you might see a message like this:

service:operator ERROR: Cannot connect to operator. Attempting to reconnect... +1ms

This usually means that you're not connected to the internet or, more likely, that the Plasma Group plasma chain operator is currently down and unable to receive transactions. We’re working really hard to beef up our operator and keep these outages minimized, but failures do happen. You can check our Twitter for updates on outages.

If the program says something else when you run it, or you spot another error, please submit a bug report on GitHub. If you’re not familiar with GitHub and could use some more information about how to submit your first bug report, check out our [resources] page.

Making your First Transaction

Note: You must keep plasma-client running in order to send an receive transactions using plasma-cli. Make sure not to close the terminal that's running plasma-client during this tutorial. Open up a new terminal window before you keep going.

Once you’ve got the client running, it’s time to make your first transaction! Before you can send money on the plasma chain, you’ll need to deposit money into the plasma chain smart contract. Basically this just means that you’re sending some funds from your Ethereum wallet to the plasma chain smart contract’s address.

Creating an Account

You can use the command line interface to send funds over to the plasma chain. If you've never used plasma-client before, you're going to need to create your first account. Here's the command for doing that:

plasma-cli createaccount

You should see something like this:

Created new account: 0x4AF55746D15991230df040EDf21aDEef5Be78043

For this tutorial you're going to want to create at least two accounts using the above command. Feel free to create more than two accounts if you'd like. You can see all of your available accounts with listaccounts:

plasma-cli listaccounts

Hopefully you'll see a list of your accounts!

(0) 0x20a229b0677D7fe42214c15942B6c40cD1340249
(1) 0x4AF55746D15991230df040EDf21aDEef5Be78043

Submitting a Deposit

You're almost ready to submit a deposit! Our plasma chain is currently deployed to the Ethereum test network (Rinkeby). Before you can deposit, you're going to need some testnet ETH. You can quickly get some using the Rinkeby testnet faucet or by tweeting at us on Twitter.

Note: We recommend using the faucet to send testnet ETH to a MetaMask wallet. This makes it easier to send ETH to other accounts. You need to send a little ETH to each account that you've created.

Once you've got some testnet ETH, you can submit your first deposit. The format of the deposit command looks like this (don’t copy this one):

plasma-cli deposit <account> <token> <amount>

In place of <account> you’ll want to insert the account you’re depositing with. This can either be the “index” of the account (the number you see in front of the address when you run listaccounts) or the address of the account. In place of <token>, you can put the contract address of the token you're depositing (ETH is just "0"). We support ERC20 tokens, but for now we're just going to leave <token> as 0 and deposit some ETH. Finally, <amount> is the total amount of ETH you're going to deposit, denominated in wei. You can use this Ethereum unit converter to easily calculate how much testnet ETH you'll be depositing.

Let's go ahead and deposit a few hundred wei:

plasma-cli deposit 0 0 500

That'll create an Ethereum transaction that you can view on a block explorer:

Sending deposit transaction...
Deposit successful!
View deposit on Etherscan:

This is going to submit a deposit transaction for 500 wei from the 0th (first) account.

You can check that the deposit was successful by looking at your balance with the getbalance command:

plasma-cli getbalance <account>

Let's try it:

plasma-cli getbalance 0

Your balance should (ideally) be 500:

0: 500

Sending a Transaction

We're almost there! Sending a transaction is as simple as running one command that looks like this:

plasma-cli send <from> <to> <token> <amount>

<from> is the account you're going to send money from. As with deposit, you can either put the full address or use the account index. <to> is the address you're sending money to. If you want to just try sending money to yourself, you can use an account index. Otherwise you can also use an Ethereum address (e.g. 0x4cdC4f412355F296C2cf261210Cc9274404E442b).

Let's go ahead and send 500 wei to your other account.

plasma-cli send 0 1 0 500

If everything goes according to plan, you'll see a transaction receipt:

Transaction receipt: 0000039a0120a229b0677D7fe42214c15942B6c40cD1340249d42b2b067cD2B2EDA3F7D3AdC9d3b400665CE8140000000000000000000000000000012c000000000000000000000190011c800cdbe44ebac984fa84e093ed1c8fa61ca14d4d5eb0e97b82d9dc54ada3f5d903dbb99d8f5aa8ecc765a5a329f4b557419ba7639ba4481b9e7e8108604e9138

This means you've just sent a plasma transaction! 🎉🎉🎉🎉

You'll probably have to wait a few second for the transaction to be detected and imported. Take a look at the other terminal where you're running plasma-client. After about thirty seconds, you should see a message saying a new transaction has been imported:

service:sync Detected new transaction: 0xee208ad1f181b909c4ee969f999da990cd65f0f9d90f6ef2e1169929f5c96602 +443ms
service:sync Attemping to pull information for transaction: 0xee208ad1f181b909c4ee969f999da990cd65f0f9d90f6ef2e1169929f5c96602 +1ms
service:sync Successfully imported transaction: 0xee208ad1f181b909c4ee969f999da990cd65f0f9d90f6ef2e1169929f5c96602 +10ms

Now, if you check the balance of your first account, you'll notice that it's empty:

plasma-cli getbalance 0

However, if you check the balance of your second account...

plasma-cli getbalance 1

You should see a result!

0: 500

Starting an Exit

Sending a transaction is fun, but it's meaningless if you can't get your money back out. Now we're going to try doing exactly that. You can easily withdraw (or "exit" your funds using the command line). The command looks like this:

plasma-cli exit <account> <token> <amount>

This command will automatically start one or more "exit transactions". Let's try withdrawing the funds we just sent to our second accont:

plasma-cli exit 1 0 500

Rememver, this means that we're withdrawing 500 wei from the account at index 1 (the second account, it's a little confusing). You should get a notification that your exit transactions were submitted:

Sending exit transaction(s)...
Exited in 1 transaction(s)
View exit(s) on Etherscan:

The decrease in your balance will be immediately reflected:

plasma-cli getbalance 1

However, if you click on those Etherscan links you'll notice that you aren't actually withdrawing any money. This is because withdrawals from plasma chains don't get processed right away. Instead, each withdrawal needs to wait out a "challenge period" before it can be processed. You can see the status of your withdrawal using this command:

plasma-cli getexits <account>

Since we sent funds to our second account, use:

plasma-cli getexits 1

Your withdrawal should pop up in the results:


Finalizing an Exit

We've set challenge periods to be pretty short for now, about 20 Ethereum blocks (5 minutes). That means you get to take a break and/or tweet at us if you have any feedback so far!

After ~5 minutes, go ahead and check on your exit again:

plasma-cli getexits 1

You should see that your exit is ready to be processed:


If it's not ready yet, wait a few more minutes and try again. Otherwise, you're ready to finalize your withdrawals. You just need to run one simple command:

plasma-cli finalizeexits <account>

Again since we started our deposit from the second account, we're going to set <account> to "1":

plasma-cli finalizeexits 1

Hopefully you'll see something like this:

Sending exit finalization transaction(s)...
Finalized 1 exit(s)
View finalization(s) on Etherscan:

Congrats, you've just gone through the entire flow of using a plasma chain! Hopefully it didn't break too many times.



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