xDai Bridge: Converting xDai

Dai is converted to xDai through the TokenBridge

xDai Bridge UI

There are currently 2 bridges on xDai with different purposes.

  1. The xDai Bridge for converting xDai to Dai. This section covers this bridge

  2. The OmniBridge for bridging all other types of ERC20s. Omnibridge section here.

What is the xDai Bridge

The TokenBridge architecture is used to move and convert assets between chains. With the xDai chain, the bridge converts Dai into xDai. Once converted, xDai is used as a native token (for transactions as well as transaction fees) on a chain where block times are fast and transactions are stable and extremely inexpensive. When a user is finished using xDai, they can convert it back to Dai using the same bridge.

The bridge uses smart contracts on both chains to process transfers, and a group of validators confirm bridge transactions. When a bridge transfer is initiated, the specified amount of Dai is locked in a smart contract on the Ethereum mainnet, and the same amount of xDai is minted on the xDai chain and sent to the user's wallet on the xDai chain. When xDai is transferred back, xDai is burned, and the corresponding amount of Dai is unlocked in the contract and released to the user's wallet on the Ethereum mainnet.

The bridge mechanism ensures that the amount of xDai can never exceed the amount of Dai locked in the bridge contract.

Dai/xDai Bridge Limits

Type

Dai to xDai Bridge

xDai to Dai Bridge

Daily Transfer Limit

10,000,000 Dai

10,000,000 xDai

Max Single Deposit

9,999,999 Dai

9,999,999 xDai

Minimum Transfer

0.005 Dai

10 xDai

Transaction Fees

variable, paid in Eth

paid in xDai

Transfer Fees

0%

0%

User Interface

A simple UI allows for seamless transfers between chains. Instructions for moving Dai to xDai and moving xDai to Dai are available. The bridge can also be used without a UI, instructions are available here.