How VIA works
VIA carries messages between smart contracts on different blockchains. This page follows one message from start to finish. It also shows who checks each message and what you control.
The problem
- Users switch networks, wallets, and apps to move between chains.
- Liquidity splits across chains, so each pool is smaller.
- Each chain needs its own integration work.
What VIA does about it
- One pattern for every chain. Your contracts talk to each other directly, on EVM and non-EVM chains.
- Users stay on the chain they already use. Your contracts do the cross-chain work.
- When VIA adds an EVM chain, you can deploy the same contract there and connect it.
The path of a message
Five steps, from your contract on one chain to your contract on another.
- 1
Your contract calls messageSend on the VIA gateway. The gateway records the message on the source chain.
- 2
Signers see the message. They wait for the number of confirmations your message asks for.
- 3
Each signer checks the source transaction again, then signs the message.
- 4
A relayer delivers the message and its signatures to the gateway on the destination chain.
- 5
The destination gateway checks that every active layer signed. Then it calls messageProcess on your contract.
Relayers can't change a message. The gateway rejects any message without the required signatures.
Midnight can't check signatures on-chain yet. On Midnight, only approved relayers can deliver messages.
Definable security
The VIA Layer signs every message. You choose what else must sign it.
VIA Layer
Always onSigners run by VIA Labs. They check every message on its source chain, then sign it.
Chain Layer
Add signers run by the chain itself. Messages need their signature too.
Project Layer
Add signers run by your team. Nothing reaches your contract without your signature.
The VIA Layer
At least two of three VIA signers must sign each message.
Two more checks
Each message can be delivered only once. Your contract accepts messages only from the gateway and only from the contracts you configure.
Run your own signers and relayers
By default, VIA Labs runs the signers and relayers for your project. Teams that want more control can run their own signers in the Project Layer. Enterprise teams can also run their own relayers.
Tokens, NFTs, and any data
VIA carries any data your contract can encode. A message can move a token, update an NFT, or carry contract state to another chain.
Fees
The sender pays one delivery fee on the source chain, in its native token. On every destination except Ethereum, that fee also covers destination gas. On Ethereum, your receiving contract holds wrapped ETH (WETH) to pay for delivery.
Delivery time
You decide. Each message sets how many block confirmations it waits for on its source chain. A confirmation is one new block added after the block that holds your transaction.
Transfers of value usually wait longer. Stablecoin and liquidity transfers often wait for many confirmations. Each new block makes the earlier ones harder to reverse. A longer wait lowers the risk that a transfer is undone. This comes from how blockchains finalize transactions, not from VIA.
For example, USDM transfers between Cardano and Midnight wait 150 confirmations on Cardano and 180 on Midnight. That takes about 50 minutes from Cardano and about 20 minutes from Midnight.
Other messages can move fast. Chains with fast finality, such as Avalanche and Stellar, make a block final within seconds. Liquidity can move between them without a long wait. Data streams, such as sensor readings or price updates, can wait zero confirmations. Each new value replaces the last one. If one value matters, you can check it on VIA Scan before you act on it.
On mainnet, messages that wait zero or one confirmation typically arrive in under two minutes.
Chains and audits
Audits
Anastasia Labs, Firepan, and Hashlock audited VIA's contracts. Every report is public.
Read the auditsTell us what you're building
Our team helps you pick your chains and a pattern, then go live.