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This page catalogues the environment variables Legacy Geth (l2geth) accepts and the RPC methods your execution client routes to it. For what Legacy Geth is and how to set it up, see the Legacy Geth guide. Legacy Geth applies only to networks that upgraded through Bedrock, such as OP Mainnet, where it serves execution requests and chain data for pre-Bedrock blocks.

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Environment variables

Legacy Geth accepts the following environment variables:
USING_OVM=true must always be set. Without it, l2geth panics at startup or returns invalid execution traces.

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Execution-client routing flag

Both op-reth and op-geth use the same --rollup.historicalrpc flag to route pre-Bedrock requests to Legacy Geth. The flag takes the URL of the Legacy Geth RPC endpoint, for example --rollup.historicalrpc=http://localhost:8545.

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RPC methods routed to Legacy Geth

This section describes op-reth. When --rollup.historicalrpc is set, op-reth forwards requests that target pre-Bedrock blocks to Legacy Geth and serves everything else directly. This covers both methods that require transaction execution (which op-reth cannot perform for pre-Bedrock blocks) and methods that read pre-Bedrock block or transaction data. Methods not listed below (for example eth_getLogs) are never routed to Legacy Geth.
op-geth behaved differently: it served pre-Bedrock block and transaction data locally from its migrated database and routed only execution methods to Legacy Geth. op-geth has reached end-of-support and this behavior is no longer documented here; see the op-geth deprecation notice.

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State and execution methods

Routed to Legacy Geth when the method’s block parameter refers to a pre-Bedrock block:
  • eth_call
  • eth_estimateGas
  • eth_createAccessList
  • eth_getBalance
  • eth_getCode
  • eth_getStorageAt
  • eth_getTransactionCount
  • eth_getProof
  • debug_traceCall

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Block data methods

Routed to Legacy Geth when the requested block is pre-Bedrock, or when the requested block hash is unknown to op-reth:
  • eth_getBlockByNumber / eth_getBlockByHash
  • eth_getBlockReceipts
  • eth_getHeaderByNumber / eth_getHeaderByHash
  • eth_getBlockTransactionCountByNumber / eth_getBlockTransactionCountByHash
  • eth_getUncleCountByBlockNumber / eth_getUncleCountByBlockHash
  • eth_getUncleByBlockNumberAndIndex / eth_getUncleByBlockHashAndIndex
  • eth_getTransactionByBlockNumberAndIndex / eth_getTransactionByBlockHashAndIndex
  • eth_getRawTransactionByBlockNumberAndIndex / eth_getRawTransactionByBlockHashAndIndex
  • debug_traceBlockByNumber / debug_traceBlockByHash

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Transaction data methods

Routed to Legacy Geth when the transaction belongs to a pre-Bedrock block, or when the transaction is unknown to op-reth:
  • eth_getTransactionByHash
  • eth_getTransactionReceipt
  • eth_getRawTransactionByHash
  • debug_traceTransaction

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eth_getBlockReceipts emulation

Legacy Geth (l2geth) predates eth_getBlockReceipts and does not implement it. op-reth forwards the request first; if Legacy Geth responds that the method does not exist, op-reth fetches the block’s transaction hashes from Legacy Geth and assembles the response from one eth_getTransactionReceipt call per transaction. Receipts are returned in transaction order and passed through verbatim, with their legacy fields intact — exactly what a forwarded eth_getTransactionReceipt returns for the same transactions. A block unknown to Legacy Geth returns null, and a block without transactions returns [].