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C-Chain

C-Chain API

This page is an overview of the C-Chain API associated with AvalancheGo.

Note

Ethereum has its own notion of networkID and chainID. These have no relationship to Avalanche's view of networkID and chainID and are purely internal to the C-Chain. On Mainnet, the C-Chain uses 1 and 43114 for these values. On the Fuji Testnet, it uses 1 and 43113 for these values. networkID and chainID can also be obtained using the net_version and eth_chainId methods.

Ethereum APIs

Endpoints

JSON-RPC Endpoints

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

/ext/bc/C/rpc

To interact with other instances of the EVM via the JSON-RPC endpoint:

/ext/bc/blockchainID/rpc

where blockchainID is the ID of the blockchain running the EVM.

WebSocket Endpoints

info

On the public API node, it only supports C-Chain websocket API calls for API methods that don't exist on the C-Chain's HTTP API

To interact with C-Chain via the websocket endpoint:

/ext/bc/C/ws

For example, to interact with the C-Chain's Ethereum APIs via websocket on localhost, you can use:

ws://127.0.0.1:9650/ext/bc/C/ws

Tip

On localhost, use ws://. When using the Public API or another host that supports encryption, use wss://.

To interact with other instances of the EVM via the websocket endpoint:

/ext/bc/blockchainID/ws

where blockchainID is the ID of the blockchain running the EVM.

Standard Ethereum APIs

Avalanche offers an API interface identical to Geth's API except that it only supports the following services:

  • web3_
  • net_
  • eth_
  • personal_
  • txpool_
  • debug_ (note: this is turned off on the public API node.)

You can interact with these services the same exact way you'd interact with Geth (see exceptions below). See the Ethereum Wiki's JSON-RPC Documentation and Geth's JSON-RPC Documentation for a full description of this API.

info

For batched requests on the public API node , the maximum number of items is 40.

Exceptions

Starting with release v0.12.2, eth_getProof has a different behavior compared to geth:

  • On archival nodes (nodes withpruning-enabled set to false), queries for state proofs older than 24 hours preceding the last accepted block will be rejected by default. This can be adjusted with historical-proof-query-window, which defines the number of blocks before the last accepted block that can be queried for state proofs. Set this option to 0 to accept a state query for any block number.
  • On pruning nodes (nodes with pruning-enabled set to true), queries for state proofs outside the 32 block window after the last accepted block are always rejected.

Avalanche - Ethereum APIs

In addition to the standard Ethereum APIs, Avalanche offers eth_baseFee, eth_maxPriorityFeePerGas, and eth_getChainConfig.

They use the same endpoint as standard Ethereum APIs:

/ext/bc/C/rpc

eth_baseFee

Get the base fee for the next block.

Signature:

eth_baseFee() -> {}

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

Example Call:

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

Example Response:

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

eth_maxPriorityFeePerGas

Get the priority fee needed to be included in a block.

Signature:

eth_maxPriorityFeePerGas() -> {}

result is hex value of the priority fee needed to be included in a block.

Example Call:

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

Example Response:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x2540be400"
}

For more information on dynamic fees see the C-Chain section of the transaction fee documentation.

Admin APIs

The Admin API provides administrative functionality for the EVM.

Endpoint

/ext/bc/C/admin

Methods

admin_startCPUProfiler

Starts a CPU profile that writes to the specified file.

Signature:

admin_startCPUProfiler() -> {}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"admin_startCPUProfiler",
    "params" :[]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/admin

admin_stopCPUProfiler

Stops the CPU profile.

Signature:

admin_stopCPUProfiler() -> {}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"admin_stopCPUProfiler",
    "params" :[]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/admin

admin_memoryProfile

Runs a memory profile writing to the specified file.

Signature:

admin_memoryProfile() -> {}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"admin_memoryProfile",
    "params" :[]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/admin

admin_lockProfile

Runs a mutex profile writing to the specified file.

Signature:

admin_lockProfile() -> {}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"admin_lockProfile",
    "params" :[]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/admin

admin_setLogLevel

Sets the log level for the EVM.

Signature:

admin_setLogLevel({
    level: string
}) -> {}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"admin_setLogLevel",
    "params" :[{
        "level": "debug"
    }]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/admin

admin_getVMConfig

Returns the current VM configuration.

Signature:

admin_getVMConfig() -> {
    config: {
        // VM configuration fields
    }
}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"admin_getVMConfig",
    "params" :[]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/admin

Avalanche-Specific APIs

Endpoint

/ext/bc/C/avax

Methods

avax.getUTXOs

Gets all UTXOs for the specified addresses.

Signature:

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

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"avax.getUTXOs",
    "params" :[{
        "addresses": ["X-avax1..."],
        "sourceChain": "X",
        "limit": 100,
        "encoding": "hex"
    }]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/avax

avax.issueTx

Issues a transaction to the network.

Signature:

avax.issueTx({
    tx: string,
    encoding: string
}) -> {
    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;' 127.0.0.1:9650/ext/bc/C/avax

avax.getAtomicTxStatus

Returns the status of the specified atomic transaction.

Signature:

avax.getAtomicTxStatus({
    txID: string
}) -> {
    status: string,
    blockHeight: number (optional)
}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"avax.getAtomicTxStatus",
    "params" :[{
        "txID": "2QouvNW..."
    }]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/avax

avax.getAtomicTx

Returns the specified atomic transaction.

Signature:

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

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"avax.getAtomicTx",
    "params" :[{
        "txID": "2QouvNW...",
        "encoding": "hex"
    }]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/avax

avax.version

Returns the version of the VM.

Signature:

avax.version() -> {
    version: string
}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"avax.version",
    "params" :[]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/avax

avax.issueBlock

Manually issues a new block.

Signature:

avax.issueBlock() -> {}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"avax.issueBlock",
    "params" :[]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/avax

avax.getAcceptedFront

Returns the last accepted block's hash and height.

Signature:

avax.getAcceptedFront() -> {
    hash: string,
    number: string
}

Example Call:

curl -X POST --data '{
    "jsonrpc":"2.0",
    "id"     :1,
    "method" :"avax.getAcceptedFront",
    "params" :[]
}' -H 'content-type:application/json;' 127.0.0.1:9650/ext/bc/C/avax

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