besu/docs/Pantheon-API/Using-JSON-RPC-API.md

description: How to access the Pantheon API using JSON-RPC
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# JSON-RPC over HTTP and WebSockets

To enable JSON-RPC over HTTP or WebSockets, use the [`--rpc-http-enabled`](../Reference/Pantheon-CLI-Syntax.md#rpc-http-enabled) 
and [`--rpc-ws-enabled`](../Reference/Pantheon-CLI-Syntax.md#rpc-ws-enabled) options.

## Postman

Use the button to import our collection of examples to [Postman](https://www.getpostman.com/). 

[![Run in Postman](https://run.pstmn.io/button.svg)](https://app.getpostman.com/run-collection/c765d7d22b055c42a510)


## 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: 

1. Start Pantheon with the [`--rpc-http-enabled`](../Reference/Pantheon-CLI-Syntax.md#rpc-http-enabled) option. 

1. Specify which APIs to enable using the [`--rpc-http-api`](../Reference/Pantheon-CLI-Syntax.md#rpc-http-api) option. 

1. Start the geth console specifying the JSON-RPC endpoint: 
   ```bash
    geth attach http://localhost:8545
   ``` 
   
Use the geth console to call [JSON-RPC API methods](../Reference/Pantheon-API-Methods.md) that geth and Pantheon share. 

!!! example 
    ```bash
    eth.syncing
    ```
    
## JSON-RPC Authentication 

[Authentication](Authentication.md) is disabled by default. 

## HTTP and WebSocket Requests

### HTTP

To make RPC requests over HTTP, you can use [`curl`](https://curl.haxx.se/download.html).

```bash
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](https://github.com/websockets/wscat), a Node.js based command-line tool.

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

```bash
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:

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

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

## Readiness and Liveness Endpoints 

Pantheon provides readiness and liveness endpoints to confirm the Pantheon node status. Both return a
`200 OK` status when ready or live and a `503 Service Unavailable` status if not ready or live. 
 
By default, the readiness check requires a peer to be connected and the node to be within 2 blocks of the best
known block. If [p2p communication is disabled](../Reference/Pantheon-CLI-Syntax.md#p2p-enabled), 
no peers are required. A live node with p2p disabled is always ready. 

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

```bash tab="Readiness Endpoint"
http://<JSON-RPC-HTTP-endpoint:port>/readiness
```
    
```bash tab="curl Request Example"
curl -v 'http://localhost:8545/readiness'
```

```bash tab="Query Parameters Example"
curl -v 'http://localhost:8545/readiness?minPeers=0&maxBlocksBehind=10'
```

The liveness check requires the JSON RPC server to be up. 

```bash tab="Liveness Endpoint"
http://<JSON-RPC-HTTP-endpoint:port>/liveness
```
    
```bash tab="curl Request Example"
curl -v 'http://localhost:8545/liveness'
```

## API Methods Enabled by Default

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

Use the [`--rpc-http-api`](../Reference/Pantheon-CLI-Syntax.md#rpc-http-api) or [`--rpc-ws-api`](../Reference/Pantheon-CLI-Syntax.md#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](../Reference/Pantheon-API-Methods.md#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](../Reference/Pantheon-API-Methods.md#eth_gettransactioncount).