Node is behind (slot lag on RPC)

Root causes

Ranked by frequency. First cause is the one to check first.

1. 01Public RPC (api.mainnet-beta.solana.com) running 10+ seconds behind tip during mainnet congestion.
2. 02Credit-metered provider serving `getSlot` from a cheaper secondary node that's a few slots behind.
3. 03Load balancer routing to a node that's mid-catchup after a restart.
4. 04`commitment: 'finalized'` used for reads — finalized is ~13 seconds behind tip by design.

Fix steps

1. 1

   Use commitment: processed or confirmed for reads

   `processed` is the newest but may be reorged; `confirmed` is the best read/safety trade-off for trading bots (2 slots behind tip). Only use `finalized` for audit-grade workloads.

2. 2

   Measure your endpoint's slot lag

   Every minute, call `getSlot` on your endpoint and compare to a reference (Helius public, QuickNode demo, or Solana explorer). If your endpoint is >5 slots behind consistently, switch.

3. 3

   Use a flat-priced endpoint with predictable latency

   Subglow RPC runs on the same validator-adjacent fleet as the gRPC stream — your reads and streams are always in sync within one slot. Credit-metered providers route to different node pools per method, so `getSlot` and `getAccountInfo` can disagree.

Related errors

• BlockhashNotFound on sendTransaction
  Your transaction failed with `BlockhashNotFound`. You used a blockhash the validator that received your submit no longer has in its recent cache — either stale, or you got it from a different node in a load-balanced pool.
• TransactionExpiredBlockheightExceededError
  Your transaction was submitted but not included before its blockhash expired. Either the network is congested and the validator dropped your tx for lack of priority fee, or your submit path is slow enough that 150 slots elapsed between fetch and inclusion.
• Method not supported on this plan
  You called `getProgramAccounts` or `getSignaturesForAddress` and got `method not supported on this plan`. These are archival methods — expensive queries that scan all accounts owned by a program or all historical signatures of a wallet. Every provider gates them behind paid or dedicated tiers.