JSON RPC

How to access the KalyChain API using JSON-RPC

JSON-RPC APIs allow you to interact with your node. JSON-RPC endpoints are not enabled by default.

!!! caution

You should secure access to your node's JSON-RPC endpoints. Users with access to your node
via JSON-RPC can make calls directly to your node, causing your node to consume resources.

To enable JSON-RPC over HTTP or WebSocket, use the --rpc-http-enabled and --rpc-ws-enabled options.

To enable JSON-RPC over an IPC socket, use the --Xrpc-ipc-enabled option.

`--Xrpc-ipc-enabled` is an early access option.

Geth console

The geth console is a REPL (Read, Evaluate, & Print Loop) JavaScript console. Use JSON-RPC APIs supported by geth and KalyChain directly in the console.

To use the geth console with Kaly:

Start Kaly with the --rpc-http-enabled or --Xrpc-ipc-enabled option.
Specify which APIs to enable using the --rpc-http-api or --Xrpc-ipc-api option.
Start the geth console specifying the JSON-RPC endpoint:

!!! example

=== "HTTP endpoint"

    ```bash
    geth attach http://localhost:8545
    ```

=== "IPC endpoint"

    ```bash
    geth attach /path/to/kaly.ipc
    ```

Use the geth console to call JSON-RPC API methods that geth and Kaly share.

!!! example

```bash
eth.syncing
```

JSON-RPC authentication

Kaly disables Authentication by default.

HTTP and WebSocket requests

HTTP

To make RPC requests over HTTP, you can use curl.

!!! example

=== "Syntax"

    ```bash
    curl -X POST --data '{"jsonrpc":"2.0","id":<request-ID>,"method":"<method-name>","params":[<method-parameters>]}' <JSON-RPC-http-endpoint:port>
    ```

=== "curl HTTP request"

    ```bash
    curl -X POST --data '{"jsonrpc":"2.0","id":"1","method":"eth_blockNumber","params":[]}' http://127.0.0.1:8555
    ```

=== "JSON result"

    ```json
    {
      "jsonrpc":"2.0",
      "id":"1",
      "result":"0x60e"
    }
    ```

You can use curl to make multiple RPC requests over HTTP at the same time. Send the requests as an array, and receive an array of responses.

!!! example

=== "curl HTTP request"

    ```bash
    curl -X POST --data '[{"jsonrpc":"2.0","id":"1","method":"eth_blockNumber","params":[]}, {"jsonrpc":"2.0","id":"2","method":"admin_peers","params":[]}]' http://127.0.0.1:8555
    ```

=== "JSON result"

    ```json
    [{
      "jsonrpc":"2.0",
      "id":"1",
      "result":"0x60e"
    },{
      "jsonrpc":"2.0",
      "id":"2",
      "result":[]
    }]
    ```

WebSocket

To make RPC requests over WebSocket, you can use wscat, a Node.js based command-line tool.

First connect to the WebSocket server using wscat (you only need to connect once per session):

wscat -c ws://<JSON-RPC-ws-endpoint:port>

After you establish a connection, the terminal displays a '>' prompt. Send individual requests as a JSON data package at each prompt.

!!! Example

=== "Syntax"

    ```bash
    {"jsonrpc":"2.0","id":<request-ID>,"method":"<method-name>","params":[<method-parameters>]}
    ```

=== "wscat WS request"

    ```bash
    {"jsonrpc":"2.0","id":"1","method":"eth_blockNumber","params":[]}
    ```

=== "JSON result"

    ```json
    {
      "jsonrpc":"2.0",
      "id":"1",
      "result":"0x23"
    }
    ```

You can use wscat to make multiple RPC requests over WebSocket at the same time. Send the requests as an array, and receive an array of responses.

!!! example

=== "wscat WS request"

    ```bash
    [{"jsonrpc":"2.0","id":"1","method":"eth_blockNumber","params":[]}, {"jsonrpc":"2.0","id":"2","method":"admin_peers","params":[]}]
    ```

=== "JSON result"

    ```json
    [{
      "jsonrpc":"2.0",
      "id":"1",
      "result":"0x23"
    },{
      "jsonrpc":"2.0",
      "id":"2",
      "result":[]
    }]
    ```

!!! note

`wscat` does not support headers. [Authentication](authenticate.md) requires you to pass an
authentication token in the request header. To use authentication with WebSocket, you need
an app that supports headers.

Readiness and liveness endpoints

Kaly provides readiness and liveness endpoints to confirm the Kaly node status. Both return a 200 OK status when ready or live and a 503 Service Unavailable status if not ready or live.

Readiness

By default, the readiness check requires a connected peer and the node to be within two blocks of the best known block. If you have disabled P2P communication, you do not need peers. A live node with P2P disabled is always ready.

Use the query parameters minPeers and maxBlocksBehind to adjust the number of peers required and the number of blocks tolerance.

=== "Readiness endpoint"

```bash
http://<JSON-RPC-HTTP-endpoint:port>/readiness
```

=== "curl request example"

```bash
curl -v 'http://localhost:8545/readiness'
```

=== "Query parameters example"

```bash
curl -v 'http://localhost:8545/readiness?minPeers=0&maxBlocksBehind=10'
```

Liveness

The liveness check requires the JSON-RPC server to be up. You can use the endpoint to verify that the node can respond to RPC calls. The status in the response will always be UP.

=== "Liveness endpoint"

```bash
http://<JSON-RPC-HTTP-endpoint:port>/liveness
```

=== "curl request example"

```bash
curl -v 'http://localhost:8545/liveness'
```

API methods enabled by default

Kaly enables the ETH, NET, and WEB3 API methods by default.

To enable the ADMIN, CLIQUE, DEBUG, EEA, IBFT, MINER, PERM, PLUGINS, PRIV, TRACE, and TXPOOL API methods, use the --rpc-http-api, --rpc-ws-api, or --Xrpc-ipc-api options.

!!! caution

`--Xrpc-ipc-api` is an early access option.

Block parameter

When you make requests that might have different results depending on the block accessed, the block parameter specifies the block. Methods such as eth_getTransactionByBlockNumberAndIndex have a block parameter.

The block parameter can have the following values:

blockNumber : quantity - The block number, specified in hexadecimal or decimal. 0 represents the genesis block.
earliest : tag - The earliest (genesis) block.
latest : tag - The last block mined.
pending : tag - The last block mined plus pending transactions. Use only with eth_getTransactionCount.
finalized : tag - The most recent crypto-economically secure block. It cannot be reorganized outside manual intervention driven by community coordination.
safe : tag - The most recent block that is safe from reorganization under honest majority and certain synchronicity assumptions.

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