# Token Bridges

## Bridging

Native utility tokens are incompatible with other blockchains. You could liken them to a country's native currency. It has value and utility within a certain context, but to be used elsewhere it must first be exchanged for a currency that is accepted where you need to use it.&#x20;

Native tokens must go through a similar process of conversion in order to be used on another blockchain other than their native blockchain. **This process is known as transferring or 'bridging tokens'**, and it allows for token interoperability between blockchains that are otherwise incompatible. Tokens that are bridged and exist on a non-native blockchain are called "wrapped tokens."&#x20;

Energy Web Token (EWT) is no different in that it is incompatible with other blockchains, and with some wallets and cryptocurrency exchanges. In order to be used outside of the Energy Web Chain, it needs to be bridged first by using a bridge. For example, if you want to bridge towards Ethereum Mainnet, you need to feed the bridge with an [ERC20 compatible token](https://eips.ethereum.org/EIPS/eip-20) that's implemented on the EWC blockchain. In order to bridge $EWT, the platform will automatically wrap the native utility token to the wrapped ERC20 version.\
ERC20, which is [explained below](#erc20-token-standard), is a technical standard for tokens on Ethereum Virtual Machine (EVM) blockchains.

## ERC20 Token Standard

The ERC20 is the technical standard for fungible tokens on EVM blockchains, like Ethereum Mainnet and Energy Web Chain. ERC20 is not a token itself; it is a smart contract that contains methods that determine how a token should behave. These methods cover specific actions like transferring funds, checking a balance and approving transactions. Tokens that implements these standards behave in an interoperable and predictable way.

ERC20 tokens have value and can be traded, but they are not associated with a specific blockchain. Compare this with a token like EWT that is associated with the Energy Web Chain, or ETH that is associated with the Ethereum blockchain.&#x20;

&#x20;You can read about the ERC20 standard and see all of it's methods on Ethereum’s documentation site [here.](https://ethereum.org/en/developers/docs/standards/tokens/erc-20/)

## Need to bridge a token? Use these bridges

{% tabs %}
{% tab title="From Energy Web" %}
{% hint style="danger" %}
When bridging back tokens, make sure you use the bridge that original created the bridged token (for example EWTB was created by legacy PoA bridge.energyweb.org)
{% endhint %}

<table><thead><tr><th width="197.4318573893042">To</th><th>bridge</th></tr></thead><tbody><tr><td>Ethereum<br><em><strong>any ERC20 token</strong></em><br></td><td>AllianceBlock bridge<br><a href="https://alliancebridge.io/">https://alliancebridge.io/</a></td></tr><tr><td>Ethereum<br><a href="https://etherscan.io/token/0x178c820f862b14f316509ec36b13123da19a6054"><strong>EWTB</strong></a> <strong>&#x3C;-> </strong><em><strong>native EWT</strong></em></td><td>Legacy PoA Bridge<br><a href="https://bridge.energyweb.org/">https://bridge.energyweb.org/</a></td></tr><tr><td>Binance Smart Chain<br><em><strong>any ERC20 token</strong></em></td><td>AllianceBlock bridge<br><a href="https://alliancebridge.io/">https://alliancebridge.io/</a><br><br><mark style="color:red;">Canswap bridge to be discontinued for Binance</mark><br><a href="https://bridge.carbonswap.exchange/"><mark style="color:red;">https://bridge.carbonswap.exchange/</mark></a></td></tr><tr><td>Moonriver network</td><td>Meter passport<br><a href="https://passport.meter.io/#/">https://passport.meter.io/#/</a></td></tr></tbody></table>

{% endtab %}

{% tab title="To Energy Web" %}

{% hint style="danger" %}
When bridging back tokens, make sure you use the bridge that original created the bridged token (for example EWTB was created by legacy PoA bridge.energyweb.org)
{% endhint %}

<table><thead><tr><th width="179.66666666666666">From</th><th>bridge</th></tr></thead><tbody><tr><td>Ethereum<br></td><td>AllianceBlock bridge<br><a href="https://alliancebridge.io/">https://alliancebridge.io/</a></td></tr><tr><td>Ethereum<br><a href="https://etherscan.io/token/0x178c820f862b14f316509ec36b13123da19a6054"><strong>EWTB</strong></a> <strong>&#x3C;-> </strong><em><strong>native EWT</strong></em></td><td>Legacy PoA Bridge<br><a href="https://bridge.energyweb.org/">https://bridge.energyweb.org/</a></td></tr></tbody></table>
{% endtab %}
{% endtabs %}

## **Bridging EWT to ERC20 Tokens**

Bridging EWT to Ethereum Mainnet creates ERC20 tokens called **Energy Web Token Bridged**; its symbol is EWTB. EWTB can be bridged back to the Energy Web Chain and redeemed as EWT at any time.&#x20;

There are several scenarios that necessitate bridging  EWT to EWTB:

1. You want to send EWT to a wallet that does not accept EWT, but does accept ERC20 compatible tokens. Not all wallets recognize EWT.&#x20;
2. You want to swap EWT on an exchange that does not accept EWT or only accepts ERC20 compatible tokens. Not all exchanges recognize EWT.&#x20;
3. You want to use your EWT to make transactions (such as sending tokens or using decentralized applications deployed on Ethereum) on the Ethereum Mainnet.&#x20;
4. You want to trade your EWT for other ERC20 compatible tokens on a decentralized platform that is running on Ethereum.

### Bridging Process

{% hint style="danger" %}
The current Ethereum bridge [https://www.bridge.energyweb.org](https://bridge.energyweb.org/) will be discontinued Q1 2022 and replaced by the AllianceBlock bridge <https://alliancebridge.io/>\
\
The (to be discontinued) Energy Web Bridge is a user interface for bridging EWT to EWTB, and EWTB to EWT ([https://www.bridge.energyweb.org](https://bridge.energyweb.org/)).&#x20;
{% endhint %}

The conversion of EWT to EWTB is managed by a smart contract that is deployed on the Energy Web Chain. You can view this contract [here](https://github.com/energywebfoundation/wrapped-native/blob/master/contracts/WrappedNative.sol). &#x20;

{% hint style="info" %}
It's important to note that bridging does not mean that tokens are transferred from one blockchain to another. The EWT that you want to bridge is locked in a smart contract on the Energy Web Chain, and the corresponding EWTB is minted on the Ethereum Mainnet. **Energy Web Tokens never leave the Energy Web Chain.**&#x20;
{% endhint %}

####

{% content-ref url="token-bridge/ewc-less-than-greater-than-ethereum" %}
[ewc-less-than-greater-than-ethereum](https://energy-web-foundation.gitbook.io/energy-web-foundation/community-resources/using-the-energy-web-chain/token-bridge/ewc-less-than-greater-than-ethereum)
{% endcontent-ref %}

{% content-ref url="token-bridge/alliancebridge-ewc-less-than-greater-than-ethereum" %}
[alliancebridge-ewc-less-than-greater-than-ethereum](https://energy-web-foundation.gitbook.io/energy-web-foundation/community-resources/using-the-energy-web-chain/token-bridge/alliancebridge-ewc-less-than-greater-than-ethereum)
{% endcontent-ref %}

{% content-ref url="broken-reference" %}
[Broken link](https://energy-web-foundation.gitbook.io/energy-web-foundation/community-resources/using-the-energy-web-chain/broken-reference)
{% endcontent-ref %}
