# EPF5 Week4 Update This week mainly focus on implementing the otterscan API for reth: 1. [feat(rpc/ots): implement ots_getContractCreator by jsvisa · Pull Request #9236 · paradigmxyz/reth](https://github.com/paradigmxyz/reth/pull/9236) 2. [feat(rpc/ots): implement ots_traceTransaction RPC by jsvisa · Pull Request #9246 · paradigmxyz/reth](https://github.com/paradigmxyz/reth/pull/9246) 3. [feat(rpc/ots): implement ots_getTransactionBySenderAndNonce by jsvisa · Pull Request #9263 · paradigmxyz/reth](https://github.com/paradigmxyz/reth/pull/9263) 4. [feat(rpc/ots): add rpc erigon_getHeaderByNumber by jsvisa · Pull Request #9300 · paradigmxyz/reth](https://github.com/paradigmxyz/reth/pull/9300) 5. [fix(rpc/ots): set block_number as u64 instead of NumberOrTag by jsvisa · Pull Request #9302 · paradigmxyz/reth](https://github.com/paradigmxyz/reth/pull/9302) In the upcoming week, I plan to focus on studying the details of trace indexing in erigon. This includes understanding the underlaying tables and data structure used by this feature, the timing of the construction process, and how to reset the data when a reorg occurs. My goal is to design the trace_filter project template within this week.