Arbitrum RPC: Endpoints, Providers, and Best Practices for Developers

What is Arbitrum and Why Do You Need an RPC Endpoint?

Arbitrum is an Ethereum Layer 2 optimistic rollup that processes transactions off-chain and posts proofs to Ethereum mainnet, resulting in lower fees and faster finality. Developers interact with Arbitrum via JSON-RPC endpoints, just like on Ethereum, using standard eth_* methods.

An RPC endpoint is the gateway that allows your dApp, wallet, or backend service to read blockchain data and submit transactions. Choosing the right endpoint is critical for performance, reliability, and cost.

• Arbitrum One (Chain ID 42161): Mainnet for production dApps.
• Arbitrum Nova (Chain ID 42170): Optimized for gaming and social applications with AnyTrust technology.
• Arbitrum Sepolia (Chain ID 421614): Testnet for development and testing.

Official Arbitrum Public RPC Endpoints

Arbitrum provides free public RPC endpoints for each network. These are suitable for prototyping, light usage, and wallet connectivity, but they come with rate limits and no WebSocket support. The official endpoints are maintained by the Arbitrum team and are a good starting point.

• Public endpoints are rate-limited and may become congested during high traffic.
• No WebSocket support means you cannot subscribe to real-time events (e.g., new blocks, pending transactions).
• Sequencer endpoints only support eth_sendRawTransaction and eth_sendRawTransactionConditional—use them for sending transactions only.

Understanding Sequencer Endpoints vs. Regular RPC Endpoints

Arbitrum's sequencer endpoints are a unique feature. They provide a direct path to the sequencer, which orders transactions before they are posted to Ethereum. This results in lower latency for transaction submission but does not support read operations like eth_call or eth_getBalance.

For production dApps, it is recommended to use the regular RPC endpoint for reads and the sequencer endpoint for writes. This separation can improve reliability and reduce the chance of hitting rate limits.

• Use sequencer endpoint for eth_sendRawTransaction only.
• Use regular RPC endpoint for all other methods (eth_call, eth_getLogs, etc.).
• Implement fallback logic: if the sequencer endpoint fails, fall back to the regular RPC for transaction submission.

Third-Party Arbitrum RPC Providers

For production-grade applications, third-party RPC providers offer higher rate limits, WebSocket support, archive data, and dedicated node options. Many providers also offer enhanced APIs for debugging and tracing. When evaluating providers, consider factors like uptime guarantees, geographic distribution, and pricing.

OnFinality provides both shared RPC API access and dedicated nodes for Arbitrum, suitable for projects that need consistent performance and scalability. Our infrastructure is designed to handle high request volumes with low latency.

• Higher rate limits compared to public endpoints.
• WebSocket support for real-time data streaming.
• Archive data access for historical queries.
• Dedicated node options for isolated performance.
• Multi-region deployment for low latency globally.

How to Choose the Right Arbitrum RPC Provider

Selecting an RPC provider depends on your project's requirements. For a small dApp or wallet, a free tier from a provider may suffice. For high-traffic applications, consider a paid plan or dedicated node. Key criteria include:

OnFinality's RPC API service offers flexible plans suitable for various stages of development, from prototyping to production. Our dedicated nodes provide full control over node configuration and resource allocation.

Best Practices for Using Arbitrum RPC in Production

To ensure high availability and performance, follow these best practices when integrating Arbitrum RPC endpoints:

Implementing these practices will help you avoid common pitfalls and provide a smooth experience for your users.

• Use multiple RPC endpoints and implement fallback logic in case one fails.
• Monitor RPC health and latency using tools like Prometheus or custom scripts.
• Separate read and write operations: use sequencer endpoint for transactions, regular endpoint for queries.
• Cache frequently accessed data (e.g., token balances, gas prices) to reduce RPC calls.
• Use WebSocket for real-time updates instead of polling the RPC endpoint.
• Set appropriate timeouts and retry mechanisms for RPC calls.

Conclusion

Arbitrum's RPC infrastructure is robust, but choosing the right endpoints and providers is crucial for building reliable dApps. Start with the official public endpoints for testing, then migrate to a third-party provider like OnFinality for production. Remember to implement fallback patterns and monitor your infrastructure to maintain uptime.

For more information on Arbitrum RPC endpoints and dedicated node options, visit our Arbitrum network page or explore our RPC API service.

Frequently Asked Questions