1. Install MetaMask

You will need to install MetaMask (or another Ethereum wallet) to connect to EW-DOS applications on the Volta test network or the main network, and to sign transactions on the blockchain.

Read more about using MetaMask here.

2. Get Tokens

If you are using applications or smart contracts on the , you will need .

• Learn how to get Volta Tokens .

• Once you have Volta tokens, you will need to .

If you are using or developing applications or smart contracts deployed on the , you will need to have .

• Learn how to get EWT .

• Once you have EWT, you will need to .

3. Using EW-DOS

Learn about Volta Testnet and Energy Web Mainnet

See an Overview of the EW-DOS Tech Stack

Energy Web supports two distinct blockchain networks:

1. The Volta Test Network (Testnet)

2. The Energy Web Production Network (Mainnet)

These networks are independent of each other. They each have their own chain specifications that the uses to configure the blockchain. You can .

You cannot transfer tokens between these two blockchains. They each use their own unique utility token that pays for transaction fees on the blockchain (read more about this ).

The Energy Web Chain's main network utility token is the , which has real fiat value. The Volta Test Network's token is the , and it has no real value. They are not interchangeable - if you have Volta tokens, this does not mean you have Energy Web Tokens, and vice versa.

Developing on Volta Test Network

Volta is the pre-production test network (testnet) of the Energy Web Chain. It’s the blockchain equivalent of a test server or test environment in traditional software development. Most blockchains have at least one test network. Ethereum, for example, for pre-deployment testing.

Volta is used as a staging network to:

• Test before they are deployed on the production chain. If you write your own smart contract, you will want to deploy it and test it on Volta first to make sure it works as expected. Because tokens on the testnet () have no real value, you can test thoroughly and incur no cost.

• Test protocol updates before they are deployed on the production chain. Each time there is an , we test it on the Volta Network first.

The utility token for the Volta Test Network is the . Volta tokens have no real value, but you will need them to "pay" for transaction costs associated with interacting with smart contracts on the Volta network. Read more about the Volta Token and how to get some

Get Started Using Volta

• - you will need to connect to the Volta network in order to access applications and smart contracts deployed on Volta

• - you have the option to run your own local node of the Volta network. You can read about the purpose and benefits of running a local node .

Developing on Energy Web Main Network

The Energy Web main network (mainnet) is the production network of the Energy Web Chain. The gas fees to pay for transactions require Energy Web Tokens (EWT), which have real value. You can read more about EWT and how to acquire it .

Get Started Using the Energy Web Chain

• - you will need to connect to the Energy Web Chain in order to access applications and smart contracts deployed on the Energy Web main network

• - you have the option to run your own local node of the Energy Web Chain. You can read about the purpose and benefits of running a local node .

Related Content

Below are steps to deploy a smart contract on the Volta Test Network (the test network for the Energy Web Chain) using Remix. Remix is a web application used to compile, deploy and test smart contracts on Ethereum networks.

In order to deploy a smart contract to the Energy Web Chain Main Network, rather than the Volta Test Network, the steps are identical, except that you will connect your MetaMask to the Energy Web Chain rather than to Volta. We recommend that you always deploy and test your smart contracts to Volta first to make sure they behave as expected.

Once your smart contract is deployed, you can use the contract's ABI and address on the blockchain to interact with its public methods. For more information on how to interact with smart contracts, go here.

1. Configure MetaMask to connect to the Volta Test Network

You can see steps for doing this are . If you do not have a MetaMask installed, you can do so .

2. Get Volta Tokens

You will need to to pay for the transaction fee for deploying the smart contract to the blockchain. For directions on how to get Volta Tokens, go . To learn more about what transaction fees are, you can go .

*Note that if you are deploying to the Energy Web Main Network, you will need to have .

3. Navigate to

4. Navigate to the "Deploy and Run Transactions" icon on the left panel (shown below).

In the "Environment" dropdown, selected "Injected Web3". Notice that when you select this, "Custom (73799) network shows up. 73799 is the Volta Test Network - this confirms that we are connected to the Volta network via MetaMask.

5. Confirm the connection on MetaMask

You will need to confirm the connection to MetaMask.

6. Create a simple smart contract

Go to the file explorer panel (select the first icon on the left panel). Add a new .sol file in the 'Contracts' folder. Below it is called VoltaContract.sol.

In the .sol file, add the following code:

7. Compile the smart contract

If there are no errors, click "Compile VoltaContract.sol" (make sure that the 'Language' selected is 'Solidity').

8. Copy the deployed contract's (Application Binary Interface)

If you want to interact with your contract in the future using an API client, you will need the contract's ABI. The ABI is in the bottom right hand corner of the Solidity Compiler page after it is compiled.

9. Deploy the smart contract

Click 'Deploy' to deploy the contract to Volta Test Network.

Confirm the transaction in MetaMask. Make sure that you have some gwei as a gas price by doing the following:

Select EDIT

Select "Edit suggested gas fee"

Make sure you have a Gas price of 6e-8 GWEI (this should be autofilled)

Confirm the transaction in MetaMask

10. See and test the deployed transaction

Once your contract is deployed, you can see it in the "Deployed Contracts" section of the same page ("Deploy and Run Transactions")

Click on "get" to test our contract's functionality. Remember from the code that is should just return a string "Volta".

11. See deployed contract on the Volta Block Explorer

Copy the address of the contract by clicking the copy icon.

Go to the . If you are deploying to the main network, the block explorer is .

Paste the contract address in the search bar at the top right:

You can see the smart contract address details, the block it was created in, and the byte code. The block explorer contract details from the example above is .

12. Use your smart contract in dapps

Now that you have your smart contract's address on the blockchain and its ABI, you can use an Ethereum API client to interact with your contract in your decentralized applications. For a tutorial on how to do this, go .

EW-DOS utility layer packages and SDKs interact with smart contracts that are deployed on the Energy Web Chain. To do this, they use API Client Libraries to connect to the blockchain and create instances of smart contracts to access their public functions.

Below we provide an overview of API Client libraries and a some code examples. Note that exact implementation varies in each package or SDK, but the fundamental concepts remain the same.

API Client Libraries

You can interact with smart contracts (i.e. call their public read and write functions) on the the Energy Web Chain and the Volta Test Network using any Ethereum API client library. Client libraries allow you to connect to and interact with the blockchain network. You can read about all the functionalities of Ethereum API client libraries in the Ethereum documentation .

The most popular JavaScript libraries for interacting with Ethereum networks are and . EW-DOS uses ethers.js, so below we will provide ethers.js examples, however concepts will be similar among different client libraries.

When interacting with a contract, you use a library to first create a Provider, which is a connection the blockchain. You then use the provider to create an instance of the smart contract that you want to interact with. Once this instance is created, you can call the public methods that are exposed in the smart contract.

1. Instantiate a Provider

A provider is a connection to the blockchain. It gives you an interface to interact with the network. To create a , you will need the JSON RPC Url. To create an , you will need the path local IPC filename (this is only available in node.js).

You can see the full ethers.js documentation on Providers .

See source code

2. Instantiate a Contract

To create a new instance of a contract that is already deployed on the blockchain, you need three pieces of information:

1. The contract's ABI- the ABI (Application Binary Interface). The ABI is a JSON object that provides the interface to your smart contract. It defines the contract's constructor, events and the behavior of its public functions. The contract's ABI is generated with the smart contract is compiled.

2. The contract's address - every smart contract has an address when it is deployed to the blockchain. You can deploy the same contract on multiple blockchains, but each contract will have a different address.

You can see the ethers.js documentation **** for creating a new instance of a deployed Contract .

See source code

2. Implement Contract Methods

The Contract method returns a new instance of that contract at the address passed in. Now that we have an instance of this contract, we can interact with its public methods:

See source code

EW-DOS Smart Contracts

For a tutorial on how to deploy a smart contract on the Volta Test Network or Energy Web Main Network, go .

The Energy Web blockchain uses the (ENS) for name-spacing assets that are anchored on our blockchain. ENS is a critical part of providing user-friendly dApps. You can interact with the ENS contracts that are deployed on the Energy Web Chain in several ways.

Below we explain:

1. Download Nethermind Client

2. Full specification for Nethermind configuration options can be found here:

   1. https://docs.nethermind.io/

3. Run the following command in your terminal -

Run RPC node in Volta Network

Run RPC node in EWC Network

Your local node should start:

Run a local node using Docker with Nethermind client

This section describes minimal setup to run an RPC node locally or on the server using Docker container run with docker-compose. This is solely for development purposes, it's not a production grade recommendation.

See Nethermind documentation for Docker:

Set up

1. Verify that prerequisites are installed:

1. Create working directory

1. Create docker-compose.yaml file

1. Start container:

1. Examine logs:

The log output should be similar to the following

Nethermind Configuration

Blockchain Oracles

By themselves, smart contracts cannot access data outside of the blockchain or send its data to services outside of the blockchain. To do this, smart contracts use middleware called an oracles, which are third-party services that fetch and send data to and from smart contracts. Oracles are similar to traditional web-based API services.

Smart contracts can contain logic that triggers certain changes or actions based on external data from an Oracle. Without oracles, blockchains and their applications that cater to specific industries that rely on real-time changes such as finance, commodity trading, or IoT, would not have access to the data necessary to react to real-time external factors.

It's important to keep in mind that oracles are agnostic of the data they transmit - they are only responsible for fetching, verifying and relaying the data to and from the blockchain.

Inbound vs. Outbound Oracles

Inbound oracles send data to the blockchain. This is the most common type of oracle. Like traditional API services, the inbound data that the oracle provides can be anything that your smart contract needs for internal logic that it cannot access from the blockchain or the smart contract itself.

For example, you want to send 10 EWT to a friend's address when the price of a specific stock goes above $10 per share. An oracle will provide you with the data about stock price, and the blockchain logic will trigger the send when the oracle delivers data indicating that the price of a stock goes above $10.

Outbound oracles send data about events that happen on the blockchain to third party applications. For example, an account could receive a payment and trigger an outbound oracle to a mechanism that activates a pv solar panel.

Oracle Data Sources

Oracles can gather data from software and hardware. A software oracle interacts with and fetches data available from any web source that exposes its data. Some common examples are weather APIs, real-time stock information and exchange rates.

Hardware oracles interact with 'physical' data sources like sensors from IoT devices, QR codes or bar codes. Some examples could be reading the temperature from a smart thermostat or fetching data from a flood sensor..

Centralized Vs. Decentralized Oracles

Centralized oracles are developed, maintained and controlled by a single entity. One oracle is responsible for fetching data from one or many data sources, and then transmitting that data to the smart contract on the blockchain. You could liken this to using a centralized database for your smart contract's external data sources.

Decentralized oracles aggregate data from multiple sources using multiple oracle nodes, so that there is no single point of failure for data retrieval, and no single point of failure for the oracle itself. Decentralized oracles are more aligned with the wider community of public blockchain.

Fundamental Oracle Functionality

Regardless of the data source, or if it is centralized or decentralized, all oracles provide three main functionalities:

1. Listen to the blockchain network for incoming requests for off-chain data

2. Fetch data from the requested off-chain source

3. Transfer the data to the blockchain via a signed transaction

Oracle Design Patterns: Communicating Data To Smart Contracts

Depending on the nature of the data itself and how the smart contract uses the data, oracles can be designed to communicate with smart contracts using three main patterns:

1. Publish-subscribe: An oracle broadcasts data, and certain smart contracts are polling or "listening to" that oracle for changes in data. An example: "Poll the temperature of region X every 10 minutes. If the temperature is above 70 degrees celsius, turn the smart thermostat to 'on'."

2. Immediate-read: Oracles hold data in their storage and provide this data on request. Users or devices query the oracle for this data at the same time that it is needed. An example: "Is device X in a list of authorized devices to provide solar power to region Y."

3. Request-response

Tutorial: Using Chainlink with the Volta Test Network

provides decentralized oracle networks. covers:

• Setting up a Chainlink node and using it from a smart contract on the Volta test network

• Aggregating data from multiple Oracles, and how to use the public Price Pair Oracle infrastructure on Volta

• Design principles of Chainlink oracles

You have the option of running a full node of the Energy Web Chain main network or Volta test network locally. Running a local node does requires a degree of technical capability. It helps to understand the benefits of doing so, and the alternatives to running a full local node.

There are a number of benefits to running your own node, which are described below.

• What does it mean to run a node?

What does it mean to run a node?

A 'client' is software that implements a blockchain's protocols and allows you to connect directly with the blockchain - that is to read data from the blockchain or initiate transactions on the blockchain, such as transferring tokens. Anyone can create client software, as long as it implements that blockchain's official protocols. Ethereum's protocols are specified in their , and there are a number of Ethereum clients to choose from.

A node is any machine that is actively running client software and is connected to the blockchain. Blockchain is often called a “peer-to-peer” network, because its network is made up of many peers running nodes simultaneously that are connected to each other.

Depending on if you are running a full node, a light node, or an archive node (see the differences between these nodes ), your client will sync with the current state of blockchain and then continue to execute every transaction that is added to the blockchain. Essentially it is having a live copy or version of the blockchain running locally on your machine.

Depending on the blockchain you are you connecting to, this can take up large amounts of space and take a long time to retrieve and sync the history of the chain on your machine. For example, synching with the Energy Web chain will require much less resources than syncing with the Ethereum mainnet, as it is a much larger and longer-running blockchain.

What do I need to run a node?

To run a node, you need to install the client software. The Energy Web mainnet and Volta testnet both use the client (formally known as Parity), because it supports the , which is a consensus algorithm specifically for Proof-of-Authority (PoA) blockchains. You can read more about the PoA consensus algorithm and why we implemented it for the Energy Web Chain .

Benefits to Running a Local Node

1. The more nodes there are, the more secure the system is as a whole. Blockchains are decentralized technology, so by design the system performs better if there are multiple instances of it rather than just one. The more nodes there are, the less points of failure or opportunities for malicious action.

2. Your transactions are more direct and more secure. Software that provides intermediary connections to the blockchain like or are, like any other web-based software, susceptible to downtime or error. By connecting to the blockchain yourself, you are removing your dependency on external providers for secure and direct connection. You also do not expose your public keys to the browser.

Alternatives to Running a Local Node

Running a local node is not necessary to use applications that run on the blockchain or transfer tokens.

To use applications deployed on the Energy Web Chain, or to transfer tokens, you can connect to the blockchain through using a remote RPC. You can see guidance for doing that on the Volta Test Network and the Energy Web Main Network .

Run a local node using the command line

Hardware Requirements

You need to meet OpenEthereum hardware requirements and have enough disk space to store database snapshots (which will grow in time).

• Multi-core CPU

• 4GB RAM

• SSD drive and free space

Download Chainspec file

Download and save the chain config to your local machine.

Note that there are different chainspec files for the and the :

• The chainspec file for Volta Test Network is .

• The chainspec file for Energy Web Main Network is .

1. Download the chainspec file.

Volta Testnet chainspec:

Energy Web Chain (production) chainspec:

Using OpenEthereum Client

1. Download

2. Full specification for OpenEthereum configuration options can be found here:

3. Run the following command in your terminal. Provide the path to the chain config that you want to use. The following command references the Volta chain config.

Your local node should start:

Connect your local node to MetaMask

Connect your MetaMask to the Volta Test Network or Energy Web Chain via remote RPC. You can read how to do this

Get the URL of your MetaMask account. You can do this by clicking the settings dropdown and selecting "Expand View."

When the view is expanded, copy the URL in the browser

Run the following command in your terminal

Run a local node using Docker with OpenEthereum client

This section describes minimal setup to run an RPC node locally or on the server using Docker container run with docker-compose. This is solely for development purposes, it's not a production grade recommendation.

See OpenEthereum documentation for Docker:

Prerequisites

Set up

1. Verify that prerequisites are installed:

2. Create working directory

3. Create docker-compose.yaml file

4. Download database snapshot - this takes some time and requires resources due to the size of the .tar file, but it will speed up synchronization process.

*Note that this step is optional. If you do not download the database snapshot, move to Step 6.

Volta (depending on your internet connection ~1 hour download time for us):

Energy Web Chain (production) (30 minutes download time for us):

5. Unpack database snapshot. This snapshot only works with OpenEthereum client.

*Note that this step is optional. If you did not complete Step 5, skip this step and move to Step 6.

Volta:

Energy Web Chain (production):

6. Set permissions:

8. Start container:

9. Examine logs:

The log output should be similar to the following (sometimes the logging output does not appear immediately, wait some time):

10. After some, you will sync with the network. Until a full sync, you will see be in a "syncing" state:

11. Check the database synchronization status in the command line using OpenEthereum's 'eth-syncing' module:

The output will show current synchronization status:

It will take some time to fully sync with the current state of the blockchain. When the synchronization is finished status will be:

Additional Resources