How I solved Ethereum RPC rate limits with traffic engineering instead of paying $250/month

A production backend began experiencing intermittent RPC failures and timeouts as wallet count grew, caused by Ethereum RPC rate limits and slow-failure behavior from providers. The author discovered that ethers.js FallbackProvider amplifies failures rather than solving them, and concluded the real fix was building RPC traffic control infrastructure—including RPS limiting, concurrency control, routing, and provider health awareness—rather than upgrading to paid plans.