No documented fallback RPC endpoints — single point of failure for all testnet developers

[osr21]

Summary

The only publicly documented RPC endpoint for Arc Testnet is https://rpc.testnet.arc.network. There are no documented alternatives, no SLA, and no guidance on what developers should do when this endpoint is unavailable.

Impact

When rpc.testnet.arc.network experiences downtime or degradation:

• Every browser wallet, DApp, script, and test suite on Arc Testnet breaks simultaneously
• Developers have no alternative endpoint to fall back to
• There is no way to distinguish between "the chain is down" and "the RPC endpoint is having issues"

This is a maturity gap compared to other EVM testnets. For reference:

• Ethereum Sepolia has 15+ documented public RPC providers
• Base Sepolia has multiple documented endpoints from Alchemy, QuickNode, dRPC, and others
• Most L2 testnets list at least 3–5 public endpoints in their docs

What We Found

While building on Arc Testnet, we discovered that dRPC provides an undocumented Arc Testnet endpoint at https://arc-testnet.drpc.org. This is not listed anywhere in the official Arc documentation. We built our own load-balanced RPC gateway across both endpoints to provide resilience.

Suggested Fix

1. Document all available public RPC endpoints in the developer docs (including dRPC's endpoint if they support it officially)
2. List RPC providers who support Arc Testnet — QuickNode, Alchemy, dRPC, Blockdaemon — even if endpoints require account signup
3. Provide guidance on what to do when the public endpoint is unavailable

Context

We operate a public Arc Testnet RPC gateway at:
https://245e1045-f370-4cc1-8fc0-1ba2bc475ce3-00-3pv56lyfqrmzj.picard.replit.dev/rpc

It load-balances across arc-public and drpc with automatic failover. We built this specifically because the single-endpoint situation is untenable for production DApps.

[osr21]

Additional endpoints found

Based on our testing, here are the available public RPC options for Arc Testnet:

Endpoint	CORS	Write TXs	Notes
https://arc-testnet.drpc.org	✅	✅ Reliable	Best option for browser DApps
https://rpc.testnet.arc.network	❌	⚠️ Intermittent	Official endpoint; write TXs sometimes fail (see #59)

Recommended pattern — try both with automatic failover:

const RPCS = [
  "https://arc-testnet.drpc.org",
  "https://rpc.testnet.arc.network",
];

async function sendWithFallback(signedTx: string): Promise<string> {
  for (const url of RPCS) {
    try {
      const p = new ethers.JsonRpcProvider(url);
      return await p.broadcastTransaction(signedTx);
    } catch (err) {
      if (RPCS.indexOf(url) === RPCS.length - 1) throw err;
      console.warn(`RPC ${url} failed, trying next...`);
    }
  }
  throw new Error("All RPC endpoints failed");
}

It would be very helpful if the Arc docs listed at minimum these two endpoints, and ideally contacted dRPC to confirm official support so we can link to it.