Blockchain Developer (Freelance) at Viseo Asia

Developed Ethereum-based smart contract functionality for a web application (Anchorpoint) using Solidity. Implemented contract functions such as token transfers, access control, and payment logic aligned with business requirements. Wrote and executed unit tests using Hardhat/Foundry, performed debugging, and optimized gas usage and performance through refactoring. Conducted code reviews with secure development best practices, performed security/vulnerability assessments, and collaborated with frontend and Node.js backend developers to integrate contracts into full-stack dApps. Implemented ERC standards (ERC-20, ERC-721) using OpenZeppelin libraries and maintained contract/API documentation.

Corda Support and Development (Freelance) at Payperchain – Germany

Provided ongoing production support and maintenance for Corda 4 CorDapps, ensuring high availability and reliability. Investigated and resolved runtime exceptions in flows/contracts/node configuration, optimized flow execution time and vault queries to reduce latency, and refactored legacy flows/states for maintainability and alignment with Corda best practices. Stabilized and improved unit/integration tests to pass reliably on ./gradlew clean build. Reduced build/test failures by improving MockNetwork usage, isolating dependencies, and minimizing resource leaks. Documented issues/workarounds for onboarding. Also built Java-based middleware to communicate with Corda nodes via RPC clients, triggering flows and serializing/deserializing REST request/response data to interact with Corda states/flows. Implemented async/sync flow handling with progress tracking, and supported flow upgrades/version compatibility between middleware and evolving CorDapps.

Senior Software Engineer / Blockchain Developer at Cloudstaff (Angeles City, Pampanga, Philippines) / Rise-X (Australia, WFH) - project: Diana

Built backend REST APIs using ASP.NET Core for scalable services, including validation, error handling, and layered architecture. Integrated Entity Framework Core for CRUD and complex queries using LINQ. Secured APIs with JWT authentication and ASP.NET Identity role-based access control. Wrote unit/integration tests with xUnit/NUnit, documented APIs using Swagger/OpenAPI, and used dependency injection and async/await to improve responsiveness. Collaborated in Agile sprints and deployment processes. Additionally translated client requirements into Ethereum smart contract logic using Solidity, deployed/managed contracts, and integrated blockchain functions with ASP.NET Core via Nethereum (transaction signing, event listening, state queries). Created reusable smart-contract service layers and wrote unit tests for both smart contracts and backend logic, runnable locally with Ganache accounts.

Software Developer at MCVEAN Pacific Int’l Offshoring Inc. (Clark City, Pampanga, Philippines)

Developed Corda-based CorDapps (Kotlin/Java) including Contract and State classes, initiating/responder flows, finality, and notarization across participants. Modeled custom schemas and persistent states using MappedSchema for optimized querying. Integrated RPC clients and exposed REST endpoints for external application interaction with the Corda network. Performed unit and flow testing using JUnit and MockNetwork. Built blockchain solutions by translating business requirements into DLT components, supported node configuration and deployment (node.conf, keystore/logging), managed Corda nodes for test and production reliability, and used Vault queries with QueryCriteria for state retrieval. Implemented confidential identities and multi-party signatures, supported contract upgrades/linear state transitions, and ensured backward compatibility. Also worked on related projects including React Native mobile development with ASP.NET Core (Blockchain Capital – Liber8) integrating REST APIs a

Associate Software Developer at Mercantile Venture Partners Asia Pacific Inc. (Clark City, Pampanga, Philippines)

Developed sample KYC and IOU CorDapps using Corda with Kotlin. Built REST API endpoints using Spring Boot and developed additional custom CorDapps. Developed Ethereum smart contracts using Solidity with Remix connected to MetaMask.