An enterprise-grade Java-based, Apache 2.0 licensed Ethereum client https://wiki.hyperledger.org/display/besu

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description: How to access the Pantheon API using JSON-RPC

JSON-RPC over HTTP and WebSockets

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

RPC Host

Use the --rpc-http-host and --rpc-ws-host options to specify the host on which the JSON-RPC listens. The default host is 127.0.0.1 for HTTP and WebSockets.

Set the host to 0.0.0.0 to allow remote connections.

!!! caution Setting the host to 0.0.0.0 exposes the RPC connection on your node to any remote connection. In a production environment, ensure you use a firewall to avoid exposing your node to the internet.

RPC Port

Use the --rpc-http-port and --rpc-ws-port options to specify the port on which the JSON-RPC listens. The default ports are:

8545 for HTTP
8546 for WebSockets

Ports must be exposed appropriately.

Postman

Use the button to import our collection of examples to Postman.

Geth Console

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

To use the geth console with Pantheon:

Start Pantheon with the --rpc-http-enabled option.
Specify which APIs to enable using the --rpc-http-api option.
Start the geth console specifying the JSON-RPC endpoint:
```
 geth attach http://localhost:8545
```

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

!!! example bash eth.syncing

JSON-RPC Authentication

Authentication is disabled by default.

HTTP and WebSocket Requests

HTTP

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

curl -X POST --data '{"jsonrpc":"2.0","method":"web3_clientVersion","params":[],"id":53}' <JSON-RPC-http-endpoint:port>

WebSockets

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

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

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

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

{"jsonrpc":"2.0","method":"web3_clientVersion","params":[],"id":53}

!!! note wscat does not support headers. Authentication requires an authentication token to be passed in the request header. To use authentication with WebSockets, an app that supports headers is required.

API Methods Enabled by Default

The ETH, NET, and WEB3 API methods are enabled by default.

Use the --rpc-http-api or --rpc-ws-api options to enable the ADMIN, CLIQUE, DEBUG, EEA, IBFT, MINER, PERM, and TXPOOL API methods.

Block Parameter

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

The block parameter can have the following values:

blockNumber : quantity - Block number. Can be specified in hexadecimal or decimal. 0 represents the genesis block.
earliest : tag - Earliest (genesis) block.
latest : tag - Last block mined.
pending : tag - Last block mined plus pending transactions. Use only with eth_getTransactionCount.

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