Request-and-claim to transfer assets from xDai chain

:white_check_mark: Update Feb 04, 2020: User Claim functionality is now active for OmniBridge transactions from xDai to Ethereum.

The latest OmniBridge update impacts the asset transfer process from the xDai chain to the Ethereum mainnet. This new functionality further decentralizes bridge operations and provides additional reliability. It is also consistent with the xDai bridge behavior.

The transfer process now requires two transactions from the users to bridge the assets.

Transaction 1: Transfer Request (on xDai). For this transaction the user pays bridge fees with their transferred tokens (with STAKE in this example) and the gas fees with xDai tokens.

After the bridge oracles confirm fee collection, the user is asked to switch the wallet’s network to the Ethereum Mainnet to finalize the transfer.

Transaction 2: Claim Tokens (on Ethereum). After switching to Ethereum, the user sends a second transaction which claims the requested amount of tokens to the user’s Ethereum account. The user must pay gas fees for this transaction in Ether, and should specify a reasonable gas price to get the tx included in a block in a suitable time. Current gas fees can be checked here and adjusted accordingly.

When the transaction is included in a block, the balance of the user’s account in the corresponding token contract increases.

:exclamation: Note, once the initial transaction in the xDai chain is included in the block on xDai, there is no way to return these tokens to the users address. A user must finalize the transfer on the Ethereum Mainnet and send them back to the xDai chain to return them. As a consequence of transfer 1, tokens are burnt on the xDai chain, so, the only way to mint them again is to transfer the tokens back through the OmniBridge.

If transaction 2 is not completed during the initial transfer, it can be completed at a later time. The next time a user connects to the OmniBridge UI app (and any time after that), a notification about the unclaimed transaction will appear, allowing for claim completion.

Unclaimed transactions are also observable on the history page where a claim button allows users to finalize the token transfer.

When claiming with MetaMask, the tx cost estimate will likely be much higher than the actual cost to process. Adjusting the gas price in MetaMask to current rates (Edit-> Advanced to set) will help save on claiming costs, but may also increase tx time. Do not change gas limit, only gas price. Regardless, costs to claim may be high. Keep this in mind and transfer in bulk. Users can also wait to claim until a later time when gas prices may be more reasonable.

In this example, MetaMask quoted a gas limit of 588,442. The actual cost to transfer was 236,523. Learn more about claim costs here.

If preferred, the transfer can also finalized using the AMB Live Monitoring tool rather than OmniBridge UI. Press the Execute button for any unfinished operation to start the claim process.


The OmniBridge UI will be switched to the new process on Monday (the 1st of February)

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It’s not implemented yet. We are waiting for UI changes from RaidGuild.

In fact, now the new OmniBridge UI is in place.

  • it uses the request-and-claim scheme to transfer tokens from xDai to Mainnet
  • it allows claim unclaimed transfer by using the history tab
  • it simplifies transfer of STAKE from Ethereum to xDai
  • it allows set “unlimited” unlock for tokens in the Settings window
  • it allows to use an alternative RPC url in the Settings window
  • it introduces ability to transfer MOONs and HNYs

Unfortunately this information is not listed on the xdai platform and I am very annoyed about the changes not being explained on xdai (as it is my first point of contact). What benefit will people get out of using the platform? One of the reason was due to low gas fee which no longer exist.