Node Tracing / JSON RPC Requirements

Archive node with JSON RPC interface should strictly follow input/output interface described in https://ethereum.github.io/execution-apis/api-documentation/
WebSocket interface (optional/highly recommended to enable) is used to subscribe to new block heads. Otherwise, Blockscout will trigger new blocks fetching by periodical polling the JSON RPC eth_blockNumber method.
Support for the following standard Ethereum JSON RPC methods (documented at https://ethereum.github.io/execution-apis/api-documentation/)
- eth_blockNumber
- eth_call
- eth_getBalance
- eth_getCode
- eth_getBlockByHash
- eth_getBlockByNumber
- eth_getTransactionByHash
- eth_getTransactionByBlockHashAndIndex
- eth_getTransactionByBlockNumberAndIndex
- eth_getTransactionReceipt
- eth_getUncleByBlockHashAndIndex
- eth_getLogs

Note pending transactions must be supported by the RPC node to enable this functionality with Blockscout

Client	Method
Nethermind OpenEthereum	`parity_pendingTransactions`
Geth Erigon	`txpool_content`

Client	Method
Erigon Nethermind OpenEthereum	• `trace_replayBlockTransactions` (fetching of internal transactions) • `trace_block` (fetching of block rewards)
Geth	• `debug_traceBlockByNumber` • or `debug_traceTransaction` `callTracer` is used by default, starting from the Blockscout 5.1.0 release. To switch to a custom JS tracer, the Blockscout maintainer should set the `export INDEXER_INTERNAL_TRANSACTIONS_TRACER_TYPE=js` environment variable. Prior to the 5.1.0 release, js tracer was a default option.
RSK	• `trace_block` (fetching of internal transactions)

Time measures for response time of crucial JSON RPC methods for indexing in Blockscout. Ways to improve speed.

eth_getBlockByNumber without transaction receipts for a block with 15 transactions: Desired response time is < 0.5s. For instance, in case of the Gnosis chain archive node, the response time for the block with ~20 transactions is ~0.4s.
eth_getTransactionReceipt for random transactions desired response time is < 0.5s. For the Gnosis chain archive node the response time is ~0.3 - 0.4s.
Batched eth_getTransactionReceipt for 15 transactions acceptable response time is Less than 1s. For the Gnosis chain archive node, it is ~0.6 - 0.7s

The desired rate limit for RPC endpoint is 200 req/sec for the indexing phase and 100 req/sec for the indexed chain.

All EVM chains must define these variables during configuration.
BlockScout currently supports Erigon, Geth, Nethermind, Hyperledger Besu, and Anvil clients. Define the node variant using the ETHEREUM_JSONRPC_VARIANT environment variable. More information