Similar to bridging from the Ethereum network, when users bridge $75 (subject to change) or more of assets from the Bitcoin network to the Avalanche network, a portion of AVAX will be airdropped to help pay for initial transactions. AVAX is used to pay for gas on the Avalanche C-Chain and is needed to perform on-chain actions. The amount airdropped should help users get started. In order to avoid running out of AVAX to cover your transaction fees, we recommend first obtaining an adequate amount of AVAX. You can acquire AVAX on Pangolin or any other exchange.

When moving assets from Avalanche back to Bitcoin, the Avalanche Bridge™ charges an in-kind transfer fee. The user interface does not allow transfers of less than the fee amount. If a user manually generates and issues such a transaction, the bridge will mark the transfer as invalid and not process it.

Offboards from the Avalanche network to the Bitcoin network are expected to take approximately 12 hours, but they may occasionally take longer. If your transaction takes longer than this, please reach out to the Product Support team: [email protected].

The Bitcoin network transaction will typically take 1 hour. The Bitcoin network will need to achieve 6 confirmations to complete.

Please reach out to Product Support for more information. Due to the sensitivity around the privacy and security of user information, please email [email protected] with your inquiry. The Product Support team will respond as soon as possible.

The transactions that correspond to Avalanche Bridge™ transfers will appear on explorers for the Avalanche and Bitcoin networks. It may take a few minutes for the transactions to appear. To search for your transaction in an explorer, copy and paste your address into the Avalanche C-Chain Explorer or Blockchain.com. To view the transactions sent by the Avalanche Bridge itself, you can look here for Avalanche and here for Bitcoin. If you still don't see your transaction, reach out on Telegram or Discord. Please be wary of anyone you are not familiar with offering to help, as they may be scammers attempting to obtain your Recovery Phrase or private keys.

This transaction only takes a few seconds, and if the Avalanche Bridge interface shows it taking longer, then check the transaction in the Explorer to see if it was successful. Users may need to add the token to the wallet on the Avalanche network for it to appear.

No, increasing the Bitcoin network fee will not speed up the transaction. Once it's included in a block there is no way to speed up the next 5 blocks getting created. Therefore, this will still typically take approximately 1 hour for all 6 confirmations.

As noted in the FAQs and Terms of Use, do not use the Avalanche Bridge if you are on the Specially Designated Nationals (SDN) List of the Office of Foreign Assets Control (OFAC) or any other sanctions list or if you are otherwise a sanctioned person or from a sanctioned jurisdiction. Those engaged in unlawful conduct, including money laundering, are also prohibited from using the Avalanche Bridge.

Users can download the Core browser extension, use Core web, or use Core mobile for Android or iOS. BTC bridging with the Avalanche Bridge™ is not supported with Metamask or any other wallet. This is because Core was custom-built to support Bitcoin and the Avalanche Bridge™ and to handle the technical problems of linking Bitcoin and EVM chains within a wallet. See here for more details on how to bridge BTC. Do not attempt to use any wallet other than the Core for BTC bridging – you may lose all your funds.

Yes, Core.app/bridge does support Bitcoin bridging. BTC bridging with the Avalanche Bridge™ is not supported with Metamask or any other wallet.

BTC bridging support on the Avalanche Bridge™ leverages much of the same technology and design of the original Avalanche Bridge architecture.

To initiate bridging from Bitcoin to Avalanche®, a transaction is sent on Bitcoin from Core transfers BTC to the bridge address controlled only by the SGX enclave. The bridge is designed to only support Pay-To-Witness-Public-Key-Hash output types on Bitcoin. In order to ensure that the BTC transfer has this output type and meets all of the bridging requirements, users should always use the bridge UI in the Core Wallet extension that is built to provide a quick and easy bridging experience. Once this transaction is accepted into a block on Bitcoin and receives the necessary number of confirmations, it will be indexed by the Bridge Nodes and reported to the Intel SGX application for processing. All transfers across the Bridge must be approved by Bridge Nodes that secure and back-up an encrypted piece of the Bridge’s keys. At this point, the SGX application mints (creates) the equivalent amount of BTC.b to the user wallet that sent the initiating Bitcoin transaction.

Similarly, when moving BTC.b from Avalanche back to Bitcoin, the user sends a transaction on Avalanche that calls the “unwrap” method of the BTC.b contract, which burns (destroys) the BTC.b tokens. The Bridge Nodes will index this transaction, and it will be processed by the SGX enclave by sending the equivalent amount of native BTC back to the user’s wallet on Bitcoin.

Yes, you can view video tutorials for bridge functionality here.

The Avalanche Bridge™ only allows transfers to the same address on the other network. After the asset is transferred to the other network, it can be sent to any address or contract in a typical send transaction.

Yes, the Bridge Nodes perform periodic key rollovers as a routine proactive security measure, including whenever new Bridge Nodes are added or removed. When this key rollover occurs, the Bridge Nodes rotate their key shards, and the bridge collateral is moved to the new corresponding address.

As noted here, anyone attempting to use the Avalanche Bridge for Ethereum bridging without going through the UI could potentially lose their funds if they send tokens to an old address no longer used by the Avalanche Bridge. To ensure the safety of users and the protection of their funds, the bridge should only be accessed and used through the UI, located here.

As noted here, the Avalanche Bridge for BTC bridging is ONLY currently available through the Core. Do not attempt to use any wallet other than the Core extension for BTC bridging – you may lose all your funds.

Please see here.

When Bitcoin is bridged to Avalanche, it is represented by an ERC20 token on the Avalanche C-chain with the symbol BTC.b. The “.b” indicates that the token was bridged from the Bitcoin network, just as Avalanche Bridge™ tokens bridged from Ethereum end in “.e”. Each BTC.b token is fully backed by a Bitcoin locked by the bridge enclave application. The BTC.b token contract can be found on Snowtrace here, and the bridge enclave application Bitcoin address can be viewed here.

In order to determine the Avalanche address that corresponds to a Bitcoin address that provided collateral to the Avalanche Bridge™, the Bridge Nodes will identify the public key of the user wallet from the signed transaction on the Bitcoin network, and use it to derive the Avalanche C-Chain address. This way, the funds on both networks are controlled by the same private key or Recovery Phrase, and that secret never leaves the sole possession of the user’s wallet. Similarly, when a user goes to transfer funds from Avalanche back to Bitcoin, the user's Bitcoin address is derived from the public key identified from the Avalanche transaction that burns the wrapped asset.

Core derives a Native Segwit address "bc1q". When sending BTC funds to Core, please make sure the sending account supports Native Segwit addresses.

Core supports the following types of addresses for withdrawals:

For more information on the types of BTC addresses please visit this link.

Bitcoin uses an entirely different address scheme than Ethereum. In order to determine the Avalanche address that corresponds to a Bitcoin address that provided collateral to the bridge, the Bridge Nodes recover the public key of the user wallet from the signed transaction on the Bitcoin network and use it to derive the Avalanche C-Chain address. This way, the funds on both networks are controlled by the same private key or mnemonic phrase, and that secret never leaves the sole possession of the user’s wallet.

No. The Avalanche Bridge™ only supports the transfer of BTC and ERC20 tokens created on Bitcoin and Ethereum, respectively, to Avalanche and back.