​

RPC workload behavior

Routing guarantees depend on the operation. Classify the workload before choosing a rollout and recovery plan.

​

Stateless reads

Methods such as eth_chainId, eth_blockNumber, current balances, transaction receipts, and many contract calls are the cleanest failover candidates. Lasso can try another eligible provider when a failure is safe to retry. Applications must still tolerate ordinary chain reorganization and provider freshness differences.

​

Historical state and logs

Historical block, state, and log coverage varies independently across provider plans. Lasso analyzes block references and provider capabilities, but a probe is evidence from selected depths and representative calls—not proof of unlimited history. eth_getLogs also has provider-specific block-range and result-size limits. Split large ranges, paginate with an overlap appropriate for reorg handling, and verify the exact range used by an indexer. A provider that serves old logs may still lack old state, and the reverse is also possible.

​

Trace and debug methods

Trace namespaces are often plan-gated or client-specific. Include only providers that support the exact trace method and parameters your application sends. Treat a successful representative probe as a starting point, then test real payload shapes and timeouts.

​

Transaction broadcast

eth_sendRawTransaction forwards a pre-signed transaction to a selected provider. Lasso does not manage account nonces, deduplicate application submissions, guarantee propagation to every upstream, or track receipts for the application. Production senders should own signing, nonce allocation, idempotency, rebroadcast policy, and receipt/finality tracking.

​

Stateful HTTP filters

Methods such as eth_newFilter create provider-local state. A filter ID from one provider is not valid on another, so ordinary provider failover can break the polling sequence. Prefer direct eth_getLogs for historical scans and WebSocket subscriptions for real-time delivery, or maintain explicit provider affinity and recovery in the application.

​

WebSocket subscriptions

Lasso multiplexes compatible upstream subscriptions and can fail over within a profile. On provider changes it can gap-fill newHeads and log subscriptions with HTTP backfill and deduplication. Pending transactions are ephemeral and do not have gap filling. Within-profile subscription failover should not be confused with system-profile HTTP fallback. Cross-profile subscription fallback is not part of the current guarantee. Clients must reconnect after network interruption, handle duplicate or delayed events, and keep their own durable checkpoint for indexer-grade processing.