Intro

The Node (sometimes referred to as External Node or EN) is a read-only replica of the main node.

What is the VIA Node

The VIA Node is a read-replica of the main (centralized) node that can be run by external parties. It functions by fetching data from the VIA API and re-applying transactions locally, starting from the genesis block. The VIA Node shares most of its codebase with the main node. Consequently, when it re-applies transactions, it does so exactly as the main node did in the past.

It has two modes of initialization:

• recovery from a DB dump, in Ethereum terms this corresponds to archival node

• recovery from a snapshot, in Ethereum terms this corresponds to light node, such nodes will only have access to transactions data from after the node was initialized. The database is currently not pruned on such nodes.

High-level overview

At a high level, the VIA Node can be seen as an application that has the following modules:

• API server that provides the publicly available Web3 interface.

• Synchronization layer that interacts with the main node and retrieves transactions and blocks to re-execute.

• Sequencer component that actually executes and persists transactions received from the synchronization layer.

• Several checker modules that ensure the consistency of the VIA Node state.

With the EN, you are able to:

• Locally recreate and verify the VIA mainnet/testnet state.

• Interact with the recreated state in a trustless way (in a sense that the validity is locally verified, and you should not rely on a third-party API VIA provides).

• Use the Web3 API without having to query the main node.

• Send L2 transactions (that will be proxied to the main node).

With the EN, you can not:

• Create L2 blocks or L1 batches on your own.

• Generate proofs.

• Submit data to L1.

A more detailed overview of the EN's components is provided in the components section.

API overview

API exposed by the VIA node strives to be Web3-compliant. If some method is exposed but behaves differently, it should be considered a bug. Please open an issue and report such cases.

eth namespace

Data getters in this namespace operate in the L2 space: require/return L2 block numbers, check balances in L2, etc.

Available methods:

Method	Notes
eth_blockNumber
eth_chainId
eth_call
eth_estimateGas
eth_gasPrice
eth_newFilter	Maximum amount of installed filters is configurable
eth_newBlockFilter	Same as above
eth_newPendingTransactionsFilter	Same as above
eth_uninstallFilter
eth_getLogs	Maximum amount of returned entities can be configured
eth_getFilterLogs	Same as above
eth_getFilterChanges	Same as above
eth_getBalance
eth_getBlockByNumber
eth_getBlockByHash
eth_getBlockTransactionCountByNumber
eth_getBlockTransactionCountByHash
eth_getCode
eth_getStorageAt
eth_getTransactionCount
eth_getTransactionByHash
eth_getTransactionByBlockHashAndIndex
eth_getTransactionByBlockNumberAndIndex
eth_getTransactionReceipt
eth_protocolVersion
eth_sendRawTransaction
eth_syncing	VIA node is considered synced if it's less than 11 blocks behind the main node.
eth_coinbase	Always returns a zero address
eth_accounts	Always returns an empty list
eth_getCompilers	Always returns an empty list
eth_hashrate	Always returns zero
eth_getUncleCountByBlockHash	Always returns zero
eth_getUncleCountByBlockNumber	Always returns zero
eth_mining	Always returns false

PubSub

Only available on the WebSocket servers.

Available methods:

Method	Notes
eth_subscribe	Maximum amount of subscriptions is configurable
eth_subscription

net namespace

Available methods:

Method	Notes
net_version
net_peer_count	Always returns 0
net_listening	Always returns false

web3 namespace

Available methods:

Method	Notes
web3_clientVersion

debug namespace

The debug namespace gives access to several non-standard RPC methods, which will allow developers to inspect and debug calls and transactions.

This namespace is disabled by default and can be configured via setting EN_API_NAMESPACES as described in the example config.

Available methods:

Method	Notes
debug_traceBlockByNumber
debug_traceBlockByHash
debug_traceCall
debug_traceTransaction

zks namespace

This namespace contains rollup-specific extensions to the Web3 API. Note that only methods specified in the documentation are considered public. There may be other methods exposed in this namespace, but undocumented methods come without any kind of stability guarantees and can be changed or removed without notice.

Always refer to the documentation linked above to see the list of stabilized methods in this namespace.

en namespace

This namespace contains methods that VIA nodes call on the main node while syncing. If this namespace is enabled, other ENs can sync from this node.