Sonic RPC — Free Endpoint & Developer Guide

Sonic is a high-speed EVM layer-1 from the team behind Fantom Opera. This guide shows how to connect to a free Sonic RPC endpoint on MoltNode — no API key and no signup required.

What is Sonic

Sonic is a layer-1 blockchain built for speed by the team behind Fantom Opera, carrying forward years of work on fast finality and high throughput. It keeps full Ethereum Virtual Machine compatibility, so the same Solidity contracts, bytecode, and developer tooling you already use elsewhere run on Sonic without modification.

Because Sonic is EVM-based, it speaks the standard eth_* JSON-RPC method set, uses regular Ethereum-style addresses, and is identified by an EVM chain ID. The native token is S, used to pay for gas, and the chain ID is 146. If you have built on any other EVM chain, your mental model transfers directly: deploy with the same compilers, query with the same RPC calls, and connect the same wallets. Porting an existing app to Sonic is usually a matter of pointing it at a new endpoint and chain ID.

Sonic RPC endpoint on MoltNode

MoltNode gives Sonic one clean URL that is also a live RPC endpoint:

https://moltnode.ag/sonic

There is no API key to provision and no account to create. The endpoint speaks JSON-RPC 2.0 over HTTP POST, and CORS is open so browser apps can call it directly. The URL is intentionally dual-purpose: open it with a GET request in a browser and you get a human-readable page describing the chain; send a POST with a JSON-RPC body and you get a machine response. Same address, two audiences.

To add it as a custom network in a wallet, point the network's RPC URL at https://moltnode.ag/sonic, set the chain ID to 146, and use S as the currency symbol.

Probe it with curl

The quickest way to confirm the Sonic JSON-RPC endpoint is live is to ask for the latest block number:

curl -s https://moltnode.ag/sonic \
  -X POST \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'

You will get back a JSON object with a hex-encoded block height in the result field. Swap in any other eth_* method — eth_chainId, eth_getBalance, eth_call — to read whatever your app needs.

Use it from your app

Any JSON-RPC client works. Here is a minimal example with viem, pointing a custom transport at the free Sonic RPC:

import { createPublicClient, http } from "viem";

const client = createPublicClient({
  transport: http("https://moltnode.ag/sonic"),
});

const blockNumber = await client.getBlockNumber();
console.log("Sonic block:", blockNumber);

The same URL drops into ethers, web3.py, wagmi, or any other library that accepts an HTTP RPC URL — no special configuration beyond the endpoint itself.

Reliability & failover

Behind the single moltnode.ag/sonic URL sits more than one upstream provider. Requests are tried in order, and if the first upstream is unreachable or returns an error, MoltNode automatically fails over to the next one. The provider API keys live server-side and are never exposed to your client, so you get the benefit of premium upstreams without managing any credentials yourself.

There is no hard rate limit, but the endpoint is a shared, free resource. Please use it responsibly: cache results where you can, avoid tight polling loops, and if you are running heavy production workloads, treat the Sonic RPC endpoint as a fast default and a failover rather than a single point of dependence.

For humans and agents

The dual GET/POST behavior makes the endpoint friendly to both people and software. A developer can paste https://moltnode.ag/sonic into a browser to read about the chain; a script or wallet POSTs Sonic JSON-RPC to the same place.

For automated discovery, MoltNode publishes a machine-readable catalog of every supported chain at https://moltnode.ag/api/chains and an agent-oriented summary at https://moltnode.ag/llms.txt. An AI agent can fetch the catalog, find the Sonic entry and its endpoint, and start issuing eth_* calls without any human setup.

Closing

The free Sonic RPC endpoint at https://moltnode.ag/sonic gives you a no-key, JSON-RPC Sonic node that works with viem, ethers, wallets, and AI agents alike — with automatic failover handled for you. Point your client at the URL and start building.