Use the transaction submission endpoint only to send transactions. Use the RPC endpoint for all other requests.
The public RPC endpoints are free, rate limited, and best effort, and are not suitable for production apps. Since October 8, 2026, https://mainnet.base.org no longer serves the debug, trace, or txpool namespaces, and read requests have a lower rate limit. If your app uses these namespaces or needs higher throughput, use a dedicated RPC provider from the Builder Stack.