Historical Block Queries Can Inflate Ethereum RPC Costs by 26x, Study Finds

Passing a historical block number to Ethereum RPC methods like eth_call silently routes requests to a provider's archive tier, which costs on average 26.7 times more compute units than querying the latest block. A development team discovered this after their RPC cost dashboard projected an overage of over $4,000 in a single billing cycle, traced back to a pattern buried in three separate indexers. The cost difference stems from the infrastructure gap between full nodes, which retain only a rolling window of recent state, and archive nodes, which preserve every historical state trie since genesis and require around 20 terabytes of storage. From a code perspective, the expensive archive call looks nearly identical to a standard call, with only an added blockNumber parameter distinguishing the two. The team identified the pattern across five categories of code paths, including token balance backfills and pool state reconstruction, and recommends using Prometheus queries to measure archive exposure before unexpected billing overages occur.