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Bilyana Gospodinova

PROFILE

Bilyana Gospodinova

Bilyana Gospodinova engineered core backend infrastructure for the hiero-ledger/hiero-mirror-node repository, focusing on scalable state management, Ethereum compatibility, and robust REST APIs. She delivered modularized service layers, optimized contract deployment, and implemented transaction-scoped caching to ensure data isolation and correctness. Using Java, Spring Framework, and Solidity, Bilyana enhanced performance with custom throttling, improved observability through metrics and logging, and stabilized CI pipelines with comprehensive test coverage. Her work addressed concurrency, database migration, and API integration challenges, resulting in reliable contract execution and data indexing. The depth of her contributions reflects strong architectural insight and a commitment to maintainable, production-ready systems.

Overall Statistics

Feature vs Bugs

58%Features

Repository Contributions

69Total
Bugs
19
Commits
69
Features
26
Lines of code
23,791
Activity Months17

Work History

April 2026

2 Commits • 2 Features

Apr 1, 2026

April 2026 monthly summary focusing on API enhancements and documentation improvements across hiero-improvement-proposals and hiero-mirror-node. Delivered REST API enhancements to support chain identification and Ethereum transaction delegation workflows, with feature-flag controlled behavior. These changes improve client integration reliability, data traceability, and maintainability while enabling secure code delegation capabilities.

March 2026

3 Commits • 3 Features

Mar 1, 2026

March 2026 — hiero-ledger/hiero-mirror-node: Delivered notable performance and visibility improvements, underpinned by robust testing and clear documentation. Key outcomes include: - API OpCodes endpoint: implemented separate throttling bucket (Bucket4j) and gzip-based response gating to manage request rates and reduce latency; added tests and docs. - NFT transaction visibility: enhanced account and transactions APIs to surface NFT-related activity with updated predicates; expanded test coverage. - Ethereum contract call support: enabled contract-call-from-smart-contract scenarios by routing to the default treasury account, improving Ethereum compatibility. - Quality and readiness: comprehensive tests and documentation accompany all changes to ensure reliability and ease of future maintenance.

February 2026

2 Commits

Feb 1, 2026

February 2026: Focused on reliability of gas pricing for historical calls and stability of CI tests in the hiero-mirror-node project. Delivered targeted fixes to ensure consistent exchange-rate usage and stabilized the test pipeline, delivering business value through accurate pricing and faster, more predictable releases.

January 2026

4 Commits • 3 Features

Jan 1, 2026

January 2026 monthly summary for hiero-ledger/hiero-mirror-node focusing on delivered features, major bug fixes, impact, and skills demonstrated. The month accelerated Ethereum-related feature readiness and improved observability and release confidence, while addressing a critical concurrency bug in GRPC message handling.

December 2025

3 Commits • 1 Features

Dec 1, 2025

December 2025: Delivered a K6-based performance testing framework for web3 apps with traffic replay capabilities, including real-world traffic input handling and essential imports. Fixed a runtime TypeError in the trafficReplay test, stabilizing automated load tests. Result: expanded performance test coverage, earlier detection of performance regressions, and more reliable test execution across environments.

November 2025

6 Commits • 2 Features

Nov 1, 2025

November 2025 performance and stability summary for hiero-mirror-node: Delivered key Web3 endpoint performance capabilities, eliminated memory inefficiencies, and hardened singleton handling to improve reliability under load. Achievements include CI-driven performance testing for /opcodes, end-to-end REST k6 tests in CI, and memory optimizations. Fixed critical singleton-related NPEs following Hedera app upgrade and refined monitoring for system account cache to enhance observability and performance.

October 2025

4 Commits • 2 Features

Oct 1, 2025

Concise monthly summary for 2025-10 focusing on business value and technical achievements for hiero-ledger/hiero-mirror-node.

September 2025

6 Commits • 3 Features

Sep 1, 2025

Month: 2025-09 | Repository: hiero-ledger/hiero-mirror-node Key features delivered - Contract Management REST API: endpoints to list contracts, retrieve contract state, and fetch contract results by timestamp; added testing coverage. - Hedera app upgrade and contract processing refactor: Hedera App 0.65.1 upgrade; extends account management with hooks and lambda storage fields; refactored contract processing for efficiency and validation. - Web3 initialization overhaul: removes legacy warmup; asynchronously initializes transaction executors per EVM version to reduce startup errors. Major bugs fixed - Hollow account input handling: ensure hollow sender accounts have a default key; allows transactions to proceed and prevents unhandled input failures for inner child transactions. - Reduce log noise for REVERTED_SUCCESS: omit logging of REVERTED_SUCCESS child errors; added tests to verify contract calls with child errors do not raise unnecessary logs or exceptions. Overall impact and accomplishments - Strengthened reliability and developer productivity through improved API capabilities, faster startup, and clearer observability. Expanded test coverage and validation for contract processing, leading to more robust operations and safer deployments. Technologies/skills demonstrated - REST API design and testing; Hedera App upgrade and hooks; asynchronous startup optimization; precise bug fixing with targeted tests; improvements to logging and observability.

August 2025

2 Commits

Aug 1, 2025

August 2025 focused on stabilizing Ethereum-compatible contract data indexing and improving accuracy of contract transaction details in hiero-ledger/hiero-mirror-node. Delivered two high-impact bug fixes and a migration-enhancement to ensure block-level indexing semantics and data persistence across imports, strengthening data reliability for analytics and user UX.

June 2025

3 Commits

Jun 1, 2025

June 2025 (2025-06) focused on stabilizing core Web3 state management, ensuring accurate consensus timing, and improving observability for the Mirror Node. Delivered three key bug fixes that restore functionality, correct timing semantics, and streamline logging and payload handling, with tests updated to validate behavior.

May 2025

1 Commits

May 1, 2025

May 2025: Delivered a critical security/validation enhancement in hiero-mirror-node by prohibiting smart contract accounts from sending transactions. The change introduces a dedicated read state AbstractAliasedAccountReadableKVState to map entities to accounts efficiently, and standardizes error handling by returning PAYER_ACCOUNT_NOT_FOUND when a contract account is detected as a sender. The update aligns with existing error semantics across the system, improving transaction validity checks, security posture, and overall reliability of the payer resolution path.

April 2025

8 Commits • 1 Features

Apr 1, 2025

April 2025 (2025-04) monthly summary for the hiero-mirror-node project. Focused on delivering upgrade-driven features, hardening key pathways, and aligning with Hedera release changes to reduce runtime risk and improve maintainability. The work enhances stability, reproducibility, and readiness for future Hedera app migrations.

March 2025

7 Commits • 4 Features

Mar 1, 2025

March 2025 monthly summary for hiero-mirror-node. Focused on stabilizing throttle behavior under concurrency, expanding test coverage for NFT minting flows, and enabling environment-driven Web3 testing. Key outcomes include remediation of race conditions by temporarily disabling deterministic throttle and introducing a custom rate-limiting throttle; development/testing tooling to bypass throttling for QA; expanded integration tests for modularizedServices NFT minting and related scenarios; new EntityCountsSingleton to satisfy Web3 dependencies; and a refactor of k6 Web3 tests to support environment variables with updated documentation.

February 2025

5 Commits • 1 Features

Feb 1, 2025

February 2025 monthly summary for hiero-ledger/hiero-mirror-node: Focused on stabilizing modularized services and improving test reliability, while introducing transaction-scoped caching to improve correctness in contract call paths. Delivered key features with aligned test suites across historical, EVM, dynamic calls, and acceptance tests, and eliminated cross-transaction data leakage by replacing shared caches with per-transaction caches.

January 2025

7 Commits • 1 Features

Jan 1, 2025

January 2025: Key deployment and test improvements for hiero-mirror-node. Consolidated test reliability across mono and modular configurations, and enhanced contract deployment efficiency by removing file upload and using maxSignedTxnSize to support larger bytecode in a single transaction.

December 2024

5 Commits • 2 Features

Dec 1, 2024

Month: 2024-12 — Focused on strengthening modular architecture and reliability for hiero-mirror-node. Delivered targeted improvements: a modularized services infrastructure enabling phased integration of reusable services; resolution of read-only mode issues for contract bytecode population; and an enhanced gas throttling mechanism to support higher throughput. These changes improve modularity, state initialization, and contract data handling, accelerating future service delivery while improving performance and reliability.

November 2024

1 Commits • 1 Features

Nov 1, 2024

November 2024: Delivered foundational state management infrastructure for the mirror node, enabling safer cross-service state sharing and laying a scalable basis for future improvements to token, contract, and file operations.

Activity

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Quality Metrics

Correctness91.2%
Maintainability84.6%
Architecture85.0%
Performance81.4%
AI Usage23.8%

Skills & Technologies

Programming Languages

GradleGroovyJavaJavaScriptKotlinMarkdownSQLShellSolidityYAML

Technical Skills

API DevelopmentAPI IntegrationAPI TestingAPI developmentAPI testingAsynchronous ProgrammingBackend DevelopmentBlockchainBug FixingCI/CDCachingCode CleanupCode RefactoringConfiguration ManagementContract Execution

Repositories Contributed To

2 repos

Overview of all repositories you've contributed to across your timeline

hiero-ledger/hiero-mirror-node

Nov 2024 Apr 2026
17 Months active

Languages Used

JavaGradleKotlinMarkdownGroovySolidityJavaScriptSQL

Technical Skills

Backend DevelopmentJava DevelopmentState ManagementSystem DesignAPI DevelopmentConfiguration Management

hiero-ledger/hiero-improvement-proposals

Apr 2026 Apr 2026
1 Month active

Languages Used

Markdown

Technical Skills

API DevelopmentDocumentation