AvalancheGo C-Chain RPC

Note: Ethereum's chain ID has no relationship to Avalanche's view of networkID and chainID and is purely internal to the C-Chain. On Mainnet, the C-Chain uses 43114. On the Fuji Testnet, it uses 43113. Both eth_chainId and net_version return this value.

Ethereum APIs

Endpoints

The examples on this page call the public APIs at api.avax.network. To call your own node, replace https://api.avax.network with http://127.0.0.1:9650, and wss://api.avax.network with ws://127.0.0.1:9650.

JSON-RPC Endpoints

To interact with C-Chain via the JSON-RPC endpoint:

/ext/bc/C/rpc

WebSocket Endpoints

To interact with C-Chain via the WebSocket endpoint:

/ext/bc/C/ws

For example, the public APIs serve the C-Chain's Ethereum WebSocket endpoint at:

wss://api.avax.network/ext/bc/C/ws

Tip: Use ws:// for a node that serves HTTP. Use wss:// for a node that serves HTTPS.

Standard Ethereum APIs

The C-Chain serves methods from the Ethereum JSON-RPC API and Geth's JSON-RPC API over HTTP and WebSocket. It doesn't serve IPC or GraphQL.

Available APIs lists every method that the C-Chain serves, grouped by API, and the APIs that are enabled by default. The apis option selects the APIs that a node serves.

The node has no accounts, so eth_resend, eth_sendTransaction, eth_sign, and eth_signTransaction always fail, and eth_pendingTransactions always returns an empty list.

Exceptions

The C-Chain executes blocks after consensus accepts them, as described in ACP-194. This changes the following:

latest and pending are the last executed block. If api-resolve-pending-to-last-executed is false, pending is the last accepted block, and state reads such as eth_getBalance and eth_call reject it. eth_getTransactionCount with pending always returns the transaction pool nonce.
safe and finalized are the last settled block, the most recent block whose execution results are included in an accepted block.
State and receipt reads wait for an accepted block to execute. eth_getLogs and log filters don't wait: for a block that hasn't executed, they return no logs, or an error if the query has no address or topic filter.
From Helicon, block headers change:
- stateRoot is the post-execution state root of the last block that the block settles, or its parent's stateRoot if it settles no blocks.
- receiptsRoot and logsBloom cover the receipts of the blocks that it settles.
- gasUsed is the sum of its transactions' gas limits, and baseFeePerGas is an upper bound on the base fee charged when it executes. Receipts report gasUsed and effectiveGasPrice from execution.

Avalanche - Ethereum APIs

In addition to the standard Ethereum APIs, Avalanche offers eth_baseFee, eth_getChainConfig, eth_suggestPriceOptions, and the newAcceptedTransactions subscription.

They use the same endpoints as the standard Ethereum APIs.

`eth_baseFee`

Get an upper bound on the base fee for the next block.

Signature:

eth_baseFee() -> quantity

result is the hex value of the upper bound on the base fee for the next block.

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"eth_baseFee"
}' -H 'content-type:application/json;' https://api.avax.network/ext/bc/C/rpc

Example Response:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x34630b8a00"
}

`eth_getChainConfig`

Returns the chain configuration.

Signature:

eth_getChainConfig() -> {}

result is the chain configuration object. The public APIs don't serve this method, so this example calls a local node.

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"eth_getChainConfig"
}' -H 'content-type:application/json;' http://127.0.0.1:9650/ext/bc/C/rpc

Example Response:

{
    "jsonrpc": "2.0",
    "id": 1,
    "result": {
        "apricotPhase1BlockTimestamp": 1607144400,
        "apricotPhase2BlockTimestamp": 1607144400,
        "apricotPhase3BlockTimestamp": 1607144400,
        "apricotPhase4BlockTimestamp": 1607144400,
        "apricotPhase5BlockTimestamp": 1607144400,
        "apricotPhase6BlockTimestamp": 1607144400,
        "apricotPhasePost6BlockTimestamp": 1607144400,
        "apricotPhasePre6BlockTimestamp": 1607144400,
        "banffBlockTimestamp": 1607144400,
        "berlinBlock": 0,
        "byzantiumBlock": 0,
        "cancunTime": 1607144400,
        "chainId": 43112,
        "constantinopleBlock": 0,
        "cortinaBlockTimestamp": 1607144400,
        "daoForkBlock": 0,
        "daoForkSupport": true,
        "durangoBlockTimestamp": 1607144400,
        "eip150Block": 0,
        "eip155Block": 0,
        "eip158Block": 0,
        "etnaTimestamp": 1607144400,
        "fortunaTimestamp": 1607144400,
        "graniteTimestamp": 1607144400,
        "heliconTimestamp": 1607144400,
        "homesteadBlock": 0,
        "iglooTimestamp": 253399622400,
        "istanbulBlock": 0,
        "londonBlock": 0,
        "muirGlacierBlock": 0,
        "petersburgBlock": 0,
        "shanghaiTime": 1607144400
    }
}

`eth_suggestPriceOptions`

Returns suggested gas price options (slow, normal, fast) for the current network conditions. Each option includes a maxPriorityFeePerGas and a maxFeePerGas value.

Signature:

eth_suggestPriceOptions() -> {
    slow: {
        maxPriorityFeePerGas: quantity,
        maxFeePerGas: quantity
    },
    normal: {
        maxPriorityFeePerGas: quantity,
        maxFeePerGas: quantity
    },
    fast: {
        maxPriorityFeePerGas: quantity,
        maxFeePerGas: quantity
    }
}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"eth_suggestPriceOptions"
}' -H 'content-type:application/json;' https://api.avax.network/ext/bc/C/rpc

Example Response:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "slow": {
      "maxPriorityFeePerGas": "0x389fd980",
      "maxFeePerGas": "0xafd56d80"
    },
    "normal": {
      "maxPriorityFeePerGas": "0x3b9aca00",
      "maxFeePerGas": "0xb2d05e00"
    },
    "fast": {
      "maxPriorityFeePerGas": "0x3e95ba80",
      "maxFeePerGas": "0xb5cb4e80"
    }
  }
}

`newAcceptedTransactions` (Subscription)

Creates a subscription that fires each time a transaction is accepted on the chain, before it is executed. This is an Avalanche-specific subscription not available in standard Ethereum. If fullTx is true, the full transaction object is sent; otherwise only the transaction hash is sent.

Available only via WebSocket.

Signature:

{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"eth_subscribe",
    "params" :["newAcceptedTransactions", false]
}

Example Call:

wscat -w -1 -c wss://api.avax.network/ext/bc/C/ws -x '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"eth_subscribe",
    "params" :["newAcceptedTransactions"]
}'

Example Notification:

{
  "jsonrpc": "2.0",
  "method": "eth_subscription",
  "params": {
    "subscription": "0x...",
    "result": "0xtransactionhash..."
  }
}

Avalanche-Specific APIs

Avalanche-Specific API Endpoint

/ext/bc/C/avax

Avalanche-Specific API Methods

`avax.getUTXOs`

Gets the UTXOs that sourceChain exported to the C-Chain for the specified addresses and that no executed block has imported yet. To get the next page, set startIndex to the returned endIndex. Stop when utxos is empty.

Signature:

avax.getUTXOs({
    addresses: [string],
    sourceChain: string,
    startIndex: {
        address: string,
        utxo: string
    } (optional),
    limit: number (optional),
    encoding: string (optional)
}) -> {
    utxos: [string],
    endIndex: {
        address: string,
        utxo: string
    },
    numFetched: string,
    encoding: string
}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"avax.getUTXOs",
    "params" :{
        "addresses": ["C-avax1m03jar35fw6q9rk63wqkl5j925xqwxhct8g5w6"],
        "sourceChain": "X",
        "limit": 100,
        "encoding": "hex"
    }
}' -H 'content-type:application/json;' https://api.avax.network/ext/bc/C/avax

`avax.issueTx`

Issues a transaction to the network.

Signature:

avax.issueTx({
    tx: string,
    encoding: string (optional)
}) -> {
    txID: string
}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"avax.issueTx",
    "params" :{
        "tx": "0x...",
        "encoding": "hex"
    }
}' -H 'content-type:application/json;' https://api.avax.network/ext/bc/C/avax

`avax.getAtomicTx`

Returns the specified atomic transaction. It returns an error until the block that contains the transaction is executed.

Signature:

avax.getAtomicTx({
    txID: string,
    encoding: string (optional)
}) -> {
    tx: string,
    encoding: string,
    blockHeight: string
}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"avax.getAtomicTx",
    "params" :{
        "txID": "2rgCo8mupzwgMfpVM7BDAgmteSDU6qrmQnJNtb37tscnN4fSwC",
        "encoding": "hex"
    }
}' -H 'content-type:application/json;' https://api.avax.network/ext/bc/C/avax

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