Coinbase Ruby SDK

The Coinbase Ruby SDK enables the simple integration of crypto into your app. By calling Coinbase's Platform APIs, the SDK allows you to provision crypto wallets, send crypto into/out of those wallets, track wallet balances, and trade crypto from one asset into another.

The SDK currently supports Customer-custodied Wallets on the Base Sepolia test network.

NOTE: The Coinbase SDK is currently in Alpha. The SDK:

• may make backwards-incompatible changes between releases
• should not be used on Mainnet (i.e. with real funds)

Currently, the SDK is intended for use on testnet for quick bootstrapping of crypto wallets at hackathons, code academies, and other development settings.

Documentation

• Platform API Documentation
• Ruby SDK Documentation

Requirements

Make sure that your developer environment satisfies all of the requirements before proceeding through the quickstart.

Ruby 2.7+

The Coinbase server-side SDK requires Ruby 2.7 or higher. To view your currently installed version of Ruby, run the following from the command-line:

ruby -v

We recommend installing and managing Ruby versions with rbenv. See Using Package Managers in the rbenv README for instructions on how to install rbenv.

Once rbenv has been installed, you can install and use Ruby 2.7 by running the following commands:

rbenv install 2.7.0
rbenv global 2.7.0

Rbsecp256k1 Gem

The Coinbase Platform SDK depends on the rbsecp256k1 gem, which requires certain dependencies to be installed on your system. Follow the instructions provided here to meet these requirements:

MacOS

On MacOS, run the following command:

brew install automake openssl libtool pkg-config gmp libffi

Linux

On Linux, run the following command:

sudo apt-get install build-essential automake pkg-config libtool \
  libffi-dev libssl-dev libgmp-dev python3-dev

:::info If you installed libsecp256k1 but the gem cannot find it, run ldconfig to update your library load paths. :::

OpenSSL Gem

The Coinbase Platform SDK relies on the openssl gem for certain cryptographic operations. If you encounter issues installing the Platform SDK, ensure that OpenSSL 3+ is installed, and that the version used by Ruby matches the version required by the gem.

If you encounter an error like this:

error: incomplete definition of type 'struct evp_md_ctx_st'
    pkey = EVP_PKEY_CTX_get0_pkey(EVP_MD_CTX_get_pkey_ctx(ctx));

re-install the openssl gem with the following command:

gem install openssl -- --with-openssl-dir=$(brew --prefix openssl@3)

Installation

There are two ways of installing the Coinbase Platform SDK: for use with the Interactive Ruby Shell, or for use in a Ruby project (e.g. Ruby on Rails).

For irb

Use the Interactive Ruby Shell (irb) to leverage Ruby’s built-in REPL and quickly explore the functionality of our SDK.

Run the following from the command line:

gem install coinbase-sdk

After running irb, require the Gem:

require 'coinbase'

For Ruby on Rails

Alternatively, if you want to install your Coinbase SDK gem to your Ruby on Rails project, add the following line to your Gemfile:

gem 'coinbase-sdk'

Or if you are using a Gemspec:

Gem::Specification.new do |spec|
  spec.add_runtime_dependency 'coinbase-sdk'
end

Then run:

bundle install

Creating a Wallet

To start, create a CDP API key. Then, initialize the Platform SDK by passing your API key name and API key's private key via the configure method:

api_key_name = "Copy your API key name here."
# Ensure that you are using double-quotes here.
api_key_private_key = "Copy your API key's private key here."

Coinbase.configure do |config|
  config.api_key_name = api_key_name
  config.api_key_private_key = api_key_private_key
end

puts "Coinbase SDK has been successfully configured with CDP API key."

Another way to initialize the SDK is by sourcing the API key from the JSON file that contains your API key, downloaded from the CDP portal.

Coinbase.configure_from_json('~/Downloads/cdp_api_key.json')

puts "Coinbase SDK has been successfully configured from JSON file."

This will allow you to authenticate with the Platform APIs and get access to the default_user:

u = Coinbase.default_user

Now, create a wallet from the User. Wallets are created with a single default address.

# Create a wallet with one address by default.
w1 = u.create_wallet

Wallets come with a single default address, accessible via default_address:

# A wallet has a default address.
a = w1.default_address

Funding a Wallet

Wallets do not have funds on them to start. For Base Sepolia testnet, we provide a faucet method to fund your wallet with testnet ETH. You are allowed one faucet claim per 24-hour window.

# Fund the wallet with a faucet transaction.
faucet_tx = w1.faucet

puts "Faucet transaction successfully completed: #{faucet_tx}"

Transferring Funds

Now that your faucet transaction has successfully completed, you can send the funds in your wallet to another wallet. The code below creates another wallet, and uses the transfer function to send testnet ETH from the first wallet to the second:

# Create a new wallet w2 to transfer funds to.
w2 = u.create_wallet

puts "Wallet successfully created: #{w2}"

t = w1.transfer(0.00001, :eth, w2).wait!

puts "Transfer successfully completed: #{t}"

See Transers for more information.

Persisting a Wallet

The SDK creates wallets with developer managed keys, which means you are responsible for securely storing the keys required to re-instantiate wallets. The following code explains how to export a wallet and store it in a secure location.

# Export the data required to re-instantiate the wallet.
data = w1.export

In order to persist the data for a wallet, you will need to implement a store method to store the exported data in a secure location. If you do not store the wallet in a secure location, you will lose access to the wallet, as well as the funds on it.

# You should implement the "store" method to securely persist the data object,
# which is required to re-instantiate the wallet at a later time. For ease of use,
# the data object is converted to a Hash first.
store(data.to_hash)

For more information on wallet persistence, see the documentation on wallets.

Alternatively, you can use the save_wallet_locally! function to persist wallets on your local file system. This is a convenience function purely for testing purposes, and should not be considered a secure method of persisting wallets.

# Set encrypt: true to encrypt the wallet export data with your CDP API key.
u.save_wallet_locally!(w1, encrypt: true)

puts "Wallet #{w1.id} successfully saved to local file storage."

Re-instantiating a Wallet

To re-instantiate a wallet, fetch your export data from your secure storage, and pass it to the import method:

# You should implement the "fetch" method to retrieve the securely persisted data object,
# keyed by the wallet ID.
fetched_data = fetch(w1.id)

# w3 will be equivalent to w1.
w3 = u.import_wallet(fetched_data)

If you used the save_wallet_locally! function to persist wallets on your local file system, then you can use the load_wallets_from_local function re-instantiate the wallets.

# wallets will contain a Hash from wallet ID to wallet.
wallets = u.load_wallets_from_local

puts "Wallets successfully loaded from local file storage."

# w4 will be equivalent to w1 and w3.
w4 = wallets[w1.id]

Development

Ruby Version

Developing in this repository requires Ruby >= 2.7.0. To install this on an M2 Mac, run the following command:

RUBY_CFLAGS=-DUSE_FFI_CLOSURE_ALLOC rbenv install 2.7.0

Set-up

Clone the repo by running:

git clone https://github.com/coinbase/coinbase-sdk-ruby.git

To install all dependencies, run:

bundle install

This SDK transitively depends on rbsecp256k1. Follow these instructions to ensure you have the necessary dependencies installed.

The SDK assumes the existence of a BASE_SEPOLIA_RPC_URL environment variable defined in your .env file. By default, this is the publicly available endpoint, which is rate-limited. To provision your own endpoint, go to the CDP Portal. Then copy and paste your Base Sepolia RPC URL in the .env file:

BASE_SEPOLIA_RPC_URL=YOUR-URL

Linting

To autocorrect all lint errors, run:

make format

To detect all lint errors, run:

make lint

Testing

To run all tests, run:

make test

To run a specific test, run (for example):

bundle exec rspec spec/coinbase/wallet_spec.rb

REPL

The repository is equipped with a REPL to allow developers to play with the SDK. To start it, run:

make repl

Generating Documentation

To generate documentation from the Ruby comments, run:

make docs