
Mariusz Jasuwienas contributed to the hiero-ledger/hiero-consensus-node and hiero-ledger/hiero-json-rpc-relay repositories, focusing on backend development and Ethereum protocol compatibility. He implemented Ethereum access list support and improved chain ID handling, addressing subtle data representation issues using Java and RLP encoding. In TypeScript, he refactored subscription flows and expanded the testing framework to validate Ethereum execution APIs, increasing reliability and maintainability. Mariusz also introduced utility helpers for contract deployment and token management, reducing code duplication. His work emphasized robust test coverage, type safety, and protocol correctness, resulting in safer deployments and more predictable cross-chain transaction processing across the codebase.
Concise monthly summary for 2025-11 focused on hiero-ledger/hiero-json-rpc-relay. Key features delivered: - Expanded the Ethereum testing framework to include batch 2 conformity tests for Ethereum execution APIs. - Added unit tests for createTransactionByType and createTransactionFromLog, increasing test coverage. Major bugs fixed: - No major bugs fixed identified in this scope for 2025-11. Overall impact and accomplishments: - Strengthened test coverage and validation for Ethereum-related operations, reducing production risk and enabling faster iteration. - Improved reliability of the JSON-RPC relay by validating multiple transaction types and log inputs, supporting safer deployment and QA cycles. Technologies/skills demonstrated: - Ethereum execution API conformance testing, unit test development, and test framework expansion. - Working with repository hiero-ledger/hiero-json-rpc-relay, committing and validating test scenarios, and ensuring QA readiness.
Concise monthly summary for 2025-11 focused on hiero-ledger/hiero-json-rpc-relay. Key features delivered: - Expanded the Ethereum testing framework to include batch 2 conformity tests for Ethereum execution APIs. - Added unit tests for createTransactionByType and createTransactionFromLog, increasing test coverage. Major bugs fixed: - No major bugs fixed identified in this scope for 2025-11. Overall impact and accomplishments: - Strengthened test coverage and validation for Ethereum-related operations, reducing production risk and enabling faster iteration. - Improved reliability of the JSON-RPC relay by validating multiple transaction types and log inputs, supporting safer deployment and QA cycles. Technologies/skills demonstrated: - Ethereum execution API conformance testing, unit test development, and test framework expansion. - Working with repository hiero-ledger/hiero-json-rpc-relay, committing and validating test scenarios, and ensuring QA readiness.
Month 2025-10 — Key feature delivery in hiero-consensus-node delivering Ethereum access list support for signature calculations. This enables signing and processing of transactions that use access lists (EIP-2930), aligning with Ethereum network expectations and improving gas efficiency and protocol compatibility. Work centered on updating transaction data structures and encoding paths to accommodate access lists, with end-to-end impact verified in signing flows.
Month 2025-10 — Key feature delivery in hiero-consensus-node delivering Ethereum access list support for signature calculations. This enables signing and processing of transactions that use access lists (EIP-2930), aligning with Ethereum network expectations and improving gas efficiency and protocol compatibility. Work centered on updating transaction data structures and encoding paths to accommodate access lists, with end-to-end impact verified in signing flows.
July 2025 monthly summary focusing on extending test coverage to ensure Hedera JSON-RPC relay compatibility, with emphasis on previously skipped conformity tests and edge cases such as pre-signed transactions and unsupported methods. This work improves reliability of the relayed interface, reduces production risk, and accelerates future deployments.
July 2025 monthly summary focusing on extending test coverage to ensure Hedera JSON-RPC relay compatibility, with emphasis on previously skipped conformity tests and edge cases such as pre-signed transactions and unsupported methods. This work improves reliability of the relayed interface, reduces production risk, and accelerates future deployments.
June 2025 performance: Delivered targeted features and refactors across two repositories, prioritizing business value through type-safe subscription flows and streamlined contract tooling. Implemented a SubscriptionResponse model for subscription requests in hiero-json-rpc-relay, and introduced deployContract and getTokenAddress helpers in hashgraph/hedera-smart-contracts to reduce duplication and improve maintainability. A JSDoc typo fix was completed to improve documentation quality. Technologies demonstrated: TypeScript/type safety, API modeling, and deployment/token utility patterns, enabling clearer APIs, faster iteration, and more reliable subscription handling.
June 2025 performance: Delivered targeted features and refactors across two repositories, prioritizing business value through type-safe subscription flows and streamlined contract tooling. Implemented a SubscriptionResponse model for subscription requests in hiero-json-rpc-relay, and introduced deployContract and getTokenAddress helpers in hashgraph/hedera-smart-contracts to reduce duplication and improve maintainability. A JSDoc typo fix was completed to improve documentation quality. Technologies demonstrated: TypeScript/type safety, API modeling, and deployment/token utility patterns, enabling clearer APIs, faster iteration, and more reliable subscription handling.
December 2024 monthly summary for hiero-consensus-node focusing on reliability and correctness in Ethereum chain ID handling. Delivered a critical bug fix that prevents misinterpretation of chain IDs and added tests to guard against regressions, improving stability for cross-chain consensus operations.
December 2024 monthly summary for hiero-consensus-node focusing on reliability and correctness in Ethereum chain ID handling. Delivered a critical bug fix that prevents misinterpretation of chain IDs and added tests to guard against regressions, improving stability for cross-chain consensus operations.

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