Moonbase Alpha – Moonbeam Test Network

Moonbase Alpha RPC
With Dwellir, you get access to our global Moonbase Alpha network which always routes your API requests to the nearest available location, ensuring low latency and the fastest speeds.

Get your API key →

Why Build on Moonbase Alpha?

Moonbase Alpha is Moonbeam’s public test network. It mirrors Moonbeam’s Ethereum-compatible Substrate runtime so you can validate end‑to‑end integrations safely before deploying to mainnet:

EVM + Substrate: Test both Ethereum JSON‑RPC and Substrate RPC flows on one chain
Fast iteration: Frequent upgrades track Moonbeam, enabling realistic pre‑prod rehearsals
Tooling parity: Works with polkadot.js, subxt, py‑substrate‑interface, and EVM SDKs

Quick Start

Connect in seconds using Dwellir’s optimized endpoints.

🔗 RPC Endpoints

Moonbase Alpha (Testnet)

Mainnet

Substrate RPC (WebSocket recommended for subscriptions).

WSS

wss://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY

HTTPS

https://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY

✓ Archive Node✓ Trace API✓ Debug API✓ WebSocket✓ Unit: DEV (18 decimals)✓ SS58 prefix 1287✓ Genesis: 0x91bc6e169807aaa54802737e1c504b2577d4fafedd5a02c10293b1cd60e39527

Quick Connect:

curl -X POST https://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"chain_getBlock","params":[],"id":1}'

Get your API key

Installation & Setup

cURL (HTTP)
JavaScript (polkadot.js)
Rust (subxt)
Python (py-substrate-interface)

curl https://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "chain_getHeader",
    "params": []
  }'

# Sample (2025-10-09)
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "number": "0xd52457",
    "parentHash": "0x56f87850ee68308211e6044273bc47bf8948e7e03a17d55e65ed70908eb921ca",
    "stateRoot": "0x013f4c9d16f934155515a7328528a7309151c8b1a693a4f6a44224a0ea2e1099",
    "extrinsicsRoot": "0x2d88bb9bc669fc3ab81a306e849b5f09248689abe1c05f81f63a88ee17891f4d"
  }
}

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

async function main() {
  const provider = new WsProvider('wss://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY');
  const api = await ApiPromise.create({ provider });

  const [chain, nodeName, version, runtime] = await Promise.all([
    api.rpc.system.chain(),
    api.rpc.system.name(),
    api.rpc.system.version(),
    api.rpc.state.getRuntimeVersion()
  ]);

  console.log(`Connected to ${chain.toString()} via ${nodeName} ${version}`);
  console.log(`specVersion=${runtime.specVersion.toString()}, txVersion=${runtime.transactionVersion.toString()}`);

  // Subscribe to new block headers
  const unsub = await api.rpc.chain.subscribeNewHeads((header) => {
    console.log(`#${header.number.toString()} ${header.hash.toHex()}`);
  });

  // Unsubscribe later
  setTimeout(async () => { await unsub(); await api.disconnect(); }, 10000);
}

main().catch(console.error);

use subxt::{config::substrate::SubstrateConfig, OnlineClient};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let api = OnlineClient::<SubstrateConfig>::from_url(
        "wss://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY"
    ).await?;

    let head = api.rpc().finalized_head().await?;
    let header = api.rpc().header(Some(head)).await?.expect("header");
    println!("Finalized block #{:?} (hash {:?})", header.number, head);
    Ok(())
}

from substrateinterface import SubstrateInterface

api = SubstrateInterface(
    url="wss://api-moonbase-alpha.n.dwellir.com/YOUR_API_KEY",
    ss58_format=1287,
    type_registry_preset="substrate-node-template"
)

runtime = api.get_runtime_version()
print("specVersion", runtime['specVersion'], "transactionVersion", runtime['transactionVersion'])

# Example account query (replace with a valid Moonbase Alpha SS58 address)
# account = api.query('System', 'Account', params=['<YOUR_SS58_ADDRESS>'])
# print(account.value['data'])

Network Information

Relay Chain

Alphanet Relay Chain

Unit / Decimals

DEV / 18

SS58 Prefix

1287

Genesis Hash

0x91bc6e169807aaa54802737e1c504b2577d4fafedd5a02c10293b1cd60e39527

Runtime (2025-10-09)

specVersion 3900 · transactionVersion 3

Explorer

moonbase.moonscan.io

Substrate JSON‑RPC API Reference

Supported core method groups include system_*, chain_*, state_*, author_*, payment_*, and rpc_methods. Frontier EVM (eth_*) and debug namespaces are available on Moonbase Alpha but are out of scope for this Substrate reference.

Available JSON-RPC Methods

System & Runtime

Identify the chain, runtime versions, and node health.

Chain Data & Finality

Inspect blocks, headers, and finality streams.

State Access & Storage

Query storage, metadata, and runtime entry points.

Authoring & Sessions

Submit extrinsics and manage session keys.

RPC Introspection

Discover supported RPC namespaces and versions.

Get your API key

Get your API key →

Common Integration Patterns

Prefer WebSocket for subscriptions (e.g., chain_subscribeNewHeads).
Cache metadata and types between runs to avoid repeated state_getMetadata/state_getRuntimeVersion calls.
For large storage scans, paginate keys with state_getKeysPaged.
Use payment_queryInfo to estimate fees before author_submitExtrinsic.

Performance Best Practices

Reconnect with exponential backoff on WS disconnects.
Batch independent calls where possible.
Scope state_getStorage queries to explicit keys; avoid full‑state traversals.

Troubleshooting

Connection errors: verify API key, TLS, and use WS for subscriptions.
Type errors: ensure metadata is fresh; update polkadot.js/subxt type bundles.
SS58 issues: confirm prefix 1287 and address checksum.
Extrinsics failing: decode dispatch errors using runtime metadata.

Smoke Tests

system_health → expect isSyncing: false and non‑zero peers.
chain_getHeader (latest) → block number increases over time.
state_getRuntimeVersion → returns specVersion: 3900, transactionVersion: 3 (as of 2025‑10‑09).

Migration Guide

From Polkadot/Westend to Moonbase Alpha:

Update endpoints to api-moonbase-alpha.n.dwellir.com.
Switch SS58 to 1287; unit symbol becomes DEV with 18 decimals.
Re‑check fee modeling via payment_queryInfo.
Confirm method availability with rpc_methods (GRANDPA/BEEFY are not exposed here).

Resources & Tools

Explorer: https://moonbase.moonscan.io
Moonbeam Docs: https://docs.moonbeam.network/
Substrate Developer Hub: https://docs.substrate.io/
Polkadot.js Apps: https://polkadot.js.org/apps/

Why Build on Moonbase Alpha?​

Quick Start​