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Smart App User Guide

In a previous article, we have introduced a method to transfer tokens from the Substrate address to the Smart address; this article will introduce another method to achieve the same result by using Darwinia Smart App.


We define Smart App as an application that transfers tokens from the Substrate address to the Smart address within the same chain.

Substrate address

Substrate-based blockchains such as Polkadot and Darwinia adopt the address format of SS58, which is usually referred to as Substrate address.

Smart address

Smart Contract-based blockchains adopt the address format of Ethereum format address, a 42-character hexadecimal address that starts with “0x”. In our documentation, we name this address format as Smart address.

Step-by-Step Instructions for Smart App

1. Preparation

Create a polkadot{.js} account(skip this step if you have already)

  • After the download completes, create a new account. Please store your password and mnemonic seed safely. Do not screenshot and share with others!

You can also import an account from pre-existing seed.

Create an account on MetaMask Wallet(skip this step if you have already)

  • Please store your password and secret recovery phrase safely when you create a new account. Do not screenshot and share with others!

You can also import an account using a secret recovery phrase.

Setup MetaMask to connect to Crab Network

  • Add a custom network in MetaMask, click Add Network.
  • Add Crab Network configuration parameters.

Network Name : Crab


RPC1: https://crab-rpc.darwinia.network

RPC2: wss://darwinia-crab.api.onfinality.io/public-ws

RPC3: https://darwinia-crab.api.onfinality.io/public/

RPC4: wss://darwiniacrab-rpc.dwellir.com

Chain ID: 44

Currency: CRAB

Block Explorer URL: https://crab.subscan.io/

  • When the connection is successfully established, you will see the figure below.

2. Select network and connect wallet

Select network: Select network to transfer assets on a certain blockchain.
Quick switch button: "Substrate" and "Smart" below the icon refer to "Substrate address" and "Smart address", and the current picture shows that the assets on the Crab chain are transferred from the substrate address to the smart address. You can click the Quick switch button to switch the source address and the target address.
Connect Wallet: After selecting the network, you can select which account to transfer assets from the drop list. The account in the drop list is read by Smart App from the plugin.

3. Fill in the transfer form

Destination address: Fill in the account address to receive the assets from the sender account. E.g. If you choose to transfer assets from a substrate address to a smart address, the destination address must be a smart address starting with "0x".⚠️ Please do NOT fill in the address of your exchange account.
Asset chosen button: Select the asset that you want to transfer.
Asset amount: Fill in the asset amount you want to transfer.
Confirm button: Confirm the transfer form, click Confirm, and sign the transaction if there is no problem.

4. Submit and confirm transfer details

5. Sign the transaction

6. Claim tokens

You need to claim your assets only when you transfer CKTON from substrate address to smart address. After transferring CKTON from the substrate address to the smart address, please switch the address from Substrate address to Smart address, and then you will find a tip to claim your CKTON.


How do we understand the substrate address and the smart address are on the same chain?

Crab Network is a Substrate-based blockchain, and it uses the substrate address format based on the SS58 Address. But in order to be compatible with Ethereum smart contract ecosystem, this blockchain added a module named Smart Module which relies on DVM(Darwinia Virtual Machine) technology. DVM is consistent with Ethereum Virtual Machine in the underlying paradigm. Meanwhile, a second address format is introduced on top of the existing network, namely smart address.

Both Wormhole and Smart App contain transfer assets, but what is the difference between Wormhole and Smart App?

Cross-chain transfer of assets between multiple blockchains can be realized through Wormhole, but Smart App focuses on transferring assets within the same chain.

What can we do after transferring tokens to the smart address?

After transferring tokens to the smart address, builders who want to develop DApps on Crab Network will use the tokens as a gas fee. For more detailed operations, please refer to the Builders.

How to add Crab Network to Metamask?

Please refer to the “Setup MetaMask to connect to Crab Network” parts of this article.

How to add token CRAB and CKTON to Crab Network on MetaMask?

After adding the Crab Network on MetaMask, the token CRAB has been there as the gas fee on the Crab Network. For token CKTON, we need to add it smart contract manually.

  • Add a custom token in MetaMask, click Import tokens.
  • Fill in the token contract address.

WCKTON contract address: 0x159933C635570D5042723359fbD1619dFe83D3f3

NOTE: The Darwinia Virtual Machine only supports 1 native token, but Crab Network has 2 native tokens, one is CRAB(Crab Network Native Token), another is CKTON(Crab Network Commitment Token). Therefore, when the token CRAB name displayed on MetaMask has no change, another token CKTON name must change. So the “W” of “WCKTON” represents wrapped, and it refers to the CKTON(Crab Network Native Token) which is stored in the contract in the form of “WCKTON”.

How to add Pangolin Test Network to MetaMask?

  • Add a custom network in MetaMask, click Add Network.
  • Add Pangolin Test Network configuration parameters.

Network Name : Pangolin

New RPC URL: http://pangolin-rpc.darwinia.network

Chain ID: 43

Currency: PRING

Block Explorer URL: https://pangolin.subscan.io/

  • When the connection is successfully established, you will see the figure below.

Contact Us

If you have any problems while using Darwinia Smart App, please send an email to hello@darwinia.network.

Series Articles

「Using Darwinia Tools 3–1」Wormhole User Guide

「Using Darwinia Tools 3–2」Wormhole User Guide II | The Substrate-to-Substrate Bridge Between Darwinia Network and Crab Network

About Darwinia Network

Darwinia Network is a decentralized cross-chain bridge network building on Substrate, which is the “cross-chain bridge hub” of the Web 3.0 Metaverse. It provides a safe and general bridging solution, connects to Polkadot, Ethereum, TRON, and other heterogeneous chains by cross-chain transfer of assets and remote chain calls.

Darwinia Network has gained high reputation and recognition along the way to build the decentralized cross-chain bridge protocol. In 2020, Darwinia was written in Polkadot light-paper as one of the friends of Polkadot and Substrate. And Darwinia was selected to join Substrate Builder Program and Web3.0 Bootcamp, and for the outstanding work in Substrate Builder Program, Darwinia Network was officially awarded the Level 2 badge by Parity. The products and tools developed by Darwinia have been rewarded three W3F Grants.

Darwinia has been contributing to the compatibility and interoperability of the Metaverse.

The application areas of Darwinia Network include DeFi, cross-chain NFT trading, games, etc. Darwinia also develops the Metaverse game Evolution Land.

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As an open cross-chain bridge protocol based on Substrate, Darwinia focuses on the construction of future Internet of Tokens. TG: http://t.me/DarwiniaNetwork