JSON-RPC

Armchain exposes a standard Ethereum-compatible JSON-RPC API over HTTP and WebSocket. If you've used Ethereum's JSON-RPC before, everything works the same way: same method names, same parameters, same response format.

Endpoint

HTTP:      http://localhost:18545   (or https://www.armchain.org/devnet for devnet)
WebSocket: ws://localhost:18546     (or wss://www.armchain.org/devnet for devnet)

Request Format

curl -X POST <RPC_URL> \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "<METHOD>",
    "params": [<PARAMS>],
    "id": 1
  }'

eth Namespace

eth_blockNumber

Returns the latest block number.

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}'

Response:

{"jsonrpc":"2.0","id":1,"result":"0x1a4"}

eth_getBalance

Returns the balance of an address in wei.

Parameters:

address: 20-byte address
blockTag: Block number or "latest", "earliest", "pending"

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getBalance","params":["0xADDRESS","latest"],"id":1}'

Response:

{"jsonrpc":"2.0","id":1,"result":"0xde0b6b3a7640000"}

eth_getTransactionCount

Returns the number of transactions sent from an address (nonce).

Parameters:

address: 20-byte address
blockTag: Block number or tag

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getTransactionCount","params":["0xADDRESS","latest"],"id":1}'

eth_sendRawTransaction

Submits a signed transaction for broadcast.

Parameters:

data: Signed transaction data (hex). Must be a Type 3 PQC transaction.

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_sendRawTransaction","params":["0x03f9..."],"id":1}'

Response:

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

eth_call

Executes a call without creating a transaction (read-only).

Parameters:

transaction: Transaction call object
blockTag: Block number or tag

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0",
    "method":"eth_call",
    "params":[{
      "to": "0xCONTRACT_ADDRESS",
      "data": "0x70a08231000000000000000000000000ADDRESS"
    }, "latest"],
    "id":1
  }'

eth_estimateGas

Estimates gas for a transaction.

Parameters:

transaction: Transaction call object

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0",
    "method":"eth_estimateGas",
    "params":[{
      "from": "0xFROM",
      "to": "0xTO",
      "value": "0xde0b6b3a7640000"
    }],
    "id":1
  }'

eth_getBlockByNumber

Returns block information by block number.

Parameters:

blockNumber: Block number (hex) or tag
fullTransactions: If true, returns full transaction objects

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getBlockByNumber","params":["latest", false],"id":1}'

eth_getTransactionByHash

Returns transaction details by hash.

Parameters:

transactionHash: 32-byte transaction hash

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getTransactionByHash","params":["0xHASH"],"id":1}'

Response (Type 3 PQC Transaction):

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "type": "0x3",
    "hash": "0x...",
    "from": "0x...",
    "to": "0x...",
    "value": "0xde0b6b3a7640000",
    "nonce": "0x1",
    "gasLimit": "0x5208",
    "maxFeePerGas": "0x4a817c800",
    "maxPriorityFeePerGas": "0x77359400",
    "chainId": "0x37",
    "blockNumber": "0x1a4",
    "blockHash": "0x...",
    "transactionIndex": "0x0"
  }
}

eth_getTransactionReceipt

Returns the receipt of a mined transaction.

Parameters:

transactionHash: 32-byte transaction hash

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getTransactionReceipt","params":["0xHASH"],"id":1}'

eth_getLogs

Returns logs matching a filter.

Parameters:

filter: Filter object with fromBlock, toBlock, address, topics

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0",
    "method":"eth_getLogs",
    "params":[{
      "fromBlock": "0x0",
      "toBlock": "latest",
      "address": "0xCONTRACT",
      "topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]
    }],
    "id":1
  }'

eth_chainId

Returns the chain ID.

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}'

Response:

{"jsonrpc":"2.0","id":1,"result":"0x37"}

eth_gasPrice

Returns the current gas price.

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_gasPrice","params":[],"id":1}'

eth_getCode

Returns the code at a given address (for contracts).

Parameters:

address: Contract address
blockTag: Block number or tag

curl -X POST https://www.armchain.org/devnet -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getCode","params":["0xCONTRACT","latest"],"id":1}'

Other Standard Methods

Method

Description

eth_accounts

Returns list of owned addresses

eth_sign

Signs data with account key

eth_signTransaction

Signs a transaction without sending

eth_getBlockByHash

Get block by hash

eth_getTransactionByBlockHashAndIndex

Get tx by block hash and index

eth_getTransactionByBlockNumberAndIndex

Get tx by block number and index

eth_getStorageAt

Get storage value at position

eth_syncing

Returns sync status

eth_mining

Returns whether node is mining/validating

eth_coinbase

Returns validator address

net Namespace

Method

Description

net_version

Returns network ID

net_listening

Whether node is listening for connections

net_peerCount

Number of connected peers

web3 Namespace

Method

Description

web3_clientVersion

Returns client version string

web3_sha3

Returns Keccak-256 of input

txpool Namespace

Method

Description

txpool_status

Returns pending and queued tx counts

txpool_content

Returns all pending and queued txs

txpool_inspect

Returns textual summary of pool

personal Namespace

Warning: Only use on local/private nodes. Never expose on public endpoints.

Method

Description

personal_newAccount

Create a new account

personal_unlockAccount

Unlock an account for signing

personal_lockAccount

Lock an account

personal_listAccounts

List all accounts

personal_sendTransaction

Sign and send a transaction

admin Namespace

Method

Description

admin_nodeInfo

Returns node information

admin_peers

Returns connected peers

admin_addPeer

Add a peer by enode URL

admin_removePeer

Remove a peer

admin_datadir

Returns the data directory path

WebSocket Subscriptions

// eth_subscribe: newHeads
ws.send(JSON.stringify({
  jsonrpc: "2.0",
  method: "eth_subscribe",
  params: ["newHeads"],
  id: 1
}));

// eth_subscribe: logs
ws.send(JSON.stringify({
  jsonrpc: "2.0",
  method: "eth_subscribe",
  params: ["logs", {
    address: "0xCONTRACT",
    topics: ["0xTOPIC_HASH"]
  }],
  id: 1
}));

ws.send(JSON.stringify({
  jsonrpc: "2.0",
  method: "eth_subscribe",
  params: ["newPendingTransactions"],
  id: 1
}));

Unsubscribe

ws.send(JSON.stringify({
  jsonrpc: "2.0",
  method: "eth_unsubscribe",
  params: ["SUBSCRIPTION_ID"],
  id: 2
}));

Rate Limits

Public RPC endpoints may enforce rate limits.

Good morning

JSON-RPC

Endpoint

Request Format

eth Namespace

eth_blockNumber

eth_getBalance

eth_getTransactionCount

eth_sendRawTransaction

eth_call

eth_estimateGas

eth_getBlockByNumber

eth_getTransactionByHash

eth_getTransactionReceipt

eth_getLogs

eth_chainId

eth_gasPrice

eth_getCode

Other Standard Methods

net Namespace

web3 Namespace

txpool Namespace

personal Namespace

admin Namespace

WebSocket Subscriptions

Unsubscribe

Rate Limits

Further Reading

Good morning

hashtagEndpoint

hashtagRequest Format

hashtageth Namespace

hashtageth_blockNumber

hashtageth_getBalance

hashtageth_getTransactionCount

hashtageth_sendRawTransaction

hashtageth_call

hashtageth_estimateGas

hashtageth_getBlockByNumber

hashtageth_getTransactionByHash

hashtageth_getTransactionReceipt

hashtageth_getLogs

hashtageth_chainId

hashtageth_gasPrice

hashtageth_getCode

hashtagOther Standard Methods

hashtagnet Namespace

hashtagweb3 Namespace

hashtagtxpool Namespace

hashtagpersonal Namespace

hashtagadmin Namespace

hashtagWebSocket Subscriptions

hashtagSubscribe to New Blocks

hashtagSubscribe to Logs

hashtagSubscribe to Pending Transactions

hashtagUnsubscribe

hashtagRate Limits

hashtagFurther Reading

Endpoint

Request Format

eth Namespace

eth_blockNumber

eth_getBalance

eth_getTransactionCount

eth_sendRawTransaction

eth_call

eth_estimateGas

eth_getBlockByNumber

eth_getTransactionByHash

eth_getTransactionReceipt

eth_getLogs

eth_chainId

eth_gasPrice

eth_getCode

Other Standard Methods

net Namespace

web3 Namespace

txpool Namespace

personal Namespace

admin Namespace

WebSocket Subscriptions

Subscribe to New Blocks

Subscribe to Logs

Subscribe to Pending Transactions

Unsubscribe

Rate Limits

Further Reading