system_health | Astar RPC Docs

Check node health status on Astar. Returns peer count, sync status, and connectivity — essential for monitoring, load balancing, and infrastructure management on Polkadot's leading dApp hub supporting EVM, WASM, and upcoming PolkaVM environments.

Returns the health status of the Astar node, including peer count, sync state, and whether the node expects to have peers.

Why Astar? Build on Polkadot's leading dApp hub supporting EVM, WASM, and upcoming PolkaVM environments with EVM + WASM + PolkaVM support, Build2Earn developer rewards, dApp Staking, and Soneium cross-layer integration.

When to Use This Method

system_health is essential for multi-chain dApp developers, DeFi builders, and teams leveraging Polkadot + Ethereum ecosystems:

Health Checks — Monitor node availability and readiness before routing traffic on Astar
Load Balancing — Route requests only to healthy, fully synced nodes for cross-chain DeFi, multi-VM smart contracts, and XCM-enabled interoperability with Ethereum and Cosmos
Sync Status — Verify a node is caught up before trusting its state queries
Infrastructure Alerts — Trigger alerts when peers drop or sync stalls

Code Examples

Common Use Cases

1. Readiness Probe for Kubernetes

Use as a health check endpoint for container orchestration on Astar:

JavaScript

import express from 'express';
import { ApiPromise, WsProvider } from '@polkadot/api';

const app = express();
const provider = new WsProvider('wss://api-astar.n.dwellir.com/YOUR_API_KEY');
const api = await ApiPromise.create({ provider });

app.get('/healthz', async (req, res) => {
  try {
    const health = await api.rpc.system.health();
    const isReady = !health.isSyncing.isTrue && health.peers.toNumber() > 0;

    if (isReady) {
      res.status(200).json({ status: 'healthy', peers: health.peers.toNumber() });
    } else {
      res.status(503).json({
        status: 'not ready',
        syncing: health.isSyncing.isTrue,
        peers: health.peers.toNumber()
      });
    }
  } catch (error) {
    res.status(503).json({ status: 'unreachable', error: error.message });
  }
});

2. Multi-Node Load Balancer

Route traffic only to healthy Astar nodes:

JavaScript

async function selectHealthyNode(endpoints) {
  const results = await Promise.allSettled(
    endpoints.map(async (endpoint) => {
      const response = await fetch(endpoint, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
          jsonrpc: '2.0',
          method: 'system_health',
          params: [],
          id: 1
        })
      });

      const { result } = await response.json();
      return { endpoint, ...result };
    })
  );

  const healthy = results
    .filter(r => r.status === 'fulfilled' && !r.value.isSyncing)
    .map(r => r.value)
    .sort((a, b) => b.peers - a.peers);

  return healthy.length > 0 ? healthy[0].endpoint : null;
}

3. Continuous Health Monitor

Periodically check node health and alert on degradation:

Python

import requests
import time

def monitor_health(endpoint, interval=30, min_peers=5):
    while True:
        try:
            payload = {
                'jsonrpc': '2.0',
                'method': 'system_health',
                'params': [],
                'id': 1
            }

            response = requests.post(endpoint, json=payload, timeout=5)
            health = response.json()['result']

            peers = health['peers']
            syncing = health['isSyncing']

            if syncing:
                print(f'WARNING: Node is syncing (peers: {peers})')
            elif peers < min_peers:
                print(f'WARNING: Low peer count: {peers}')
            else:
                print(f'OK: peers={peers}, syncing={syncing}')

        except Exception as e:
            print(f'ERROR: Node unreachable — {e}')

        time.sleep(interval)

monitor_health('https://api-astar.n.dwellir.com/YOUR_API_KEY')

Error Handling

Error Code	Description	Solution
-32603	Internal error	Node may be starting up — retry after delay
-32601	Method not found	Verify the node exposes the `system` RPC module
HTTP 429 / -32029	Rate limit exceeded	Reduce polling frequency and retry with backoff
Connection refused	Node is down	Check node process and network connectivity

system_version — Get node software version
system_chain — Get chain name
system_syncState — Get detailed sync progress
system_peers — Get detailed peer information

system_health - Astar RPC Method