Blockchain Engineer

We're Hiring: Blockchain Engineer (Full-Time | Remote)
Location: Remote
Employment Type: Full-Time
BangoPure Limited is seeking an experienced and detail-oriented Blockchain Engineer to join our growing international team.
BangoPure delivers a diverse portfolio of digital platforms and sustainability-driven solutions focused on sustainability, traceability, digital transformation, international trade facilitation, and circular economy initiatives.
We are looking for a Blockchain Engineer with a strong Java and Spring Boot background who will own the on-chain anchoring and verification layer of the platform and contribute to the backend services around it. Our use of blockchain is deliberately focused: hash anchoring on Polygon, not token issuance or NFT minting.
The platform is a production-ready modular monolith with twelve feature modules, an event-driven mint pipeline, and a full integration test suite. This is neither a greenfield rewrite nor legacy maintenance.
Key Responsibilities
• Design, develop, test, and maintain the on-chain hash anchoring and verification layer using web3j, Solidity 0.8, and Polygon.
• Extend and harden the passport mint pipeline, a fixed-order saga over Apache Kafka covering product submission, assessment, environmental declaration calculation, GS1 identifier assignment, passport generation and storage, on-chain anchoring, and EU DPP Registry registration.
• Keep the anchoring step idempotent and resilient, including compensation paths, retries, duplicate events, transaction confirmation, and failure recovery.
• Build public verification capabilities that allow consumers and regulators to prove a passport record matches its anchored hash.
• Implement tamper-evident audit trails with hash chaining, and support compliance features such as data-tier serialization, GDPR erasure flows, and data-export SLAs.
• Integrate with external systems including GS1 Digital Link resolvers, the EU DPP Registry, and sector rule sets for batteries and electronics, strictly according to their published specifications.
• Deliver new hexagonal feature modules, such as verification, billing, supplier onboarding, and developer APIs, each with its own tables, events, and module boundary, released behind feature gates.
• Contribute to multi-tenancy work, including PostgreSQL row-level security, tenant-scoped search, and tests proving strict tenant data isolation.
• Conduct smart contract testing and security reviews for the anchoring contracts.
• Write architecture decision records before implementation and keep technical documentation aligned with the specification documents in the repository.
• Collaborate with Product Owners, backend engineers, DevOps, QA, and business stakeholders throughout the development lifecycle.
Must-Have Qualifications
• Minimum 3+ years of hands-on experience building backend services in Java, most of it with Spring Boot.
• Hands-on experience with EVM-compatible blockchains (Ethereum, Polygon, or similar), including Solidity smart contract development and integrating contracts from a backend service.
• Strong working knowledge of relational databases: reading query plans, designing safe migrations, and defining transaction boundaries.
• Experience with asynchronous messaging (Apache Kafka, RabbitMQ, or AWS SQS), including at-least-once delivery, duplicate events, and consumer lag.
• A testing discipline that includes integration tests against real infrastructure, written before work is considered complete.
• Proven ability to translate specifications, regulations, or pinned API contracts into code that matches them exactly, and to raise ambiguities rather than guess.
• Written English sufficient for asynchronous collaboration across multiple time zones.
• Ability to work independently within a fully remote international team.
Technical Requirements
• Language & Framework: Java 21 (including virtual threads), Spring Boot 3.4, Spring Modulith, Spring Security.
• Blockchain: web3j, Solidity 0.8, Polygon; transaction lifecycle management, confirmation handling, and smart contract testing with frameworks such as Hardhat or Foundry.
• Data: PostgreSQL with row-level security, JPA and jOOQ, Flyway migrations.
• Eventing: Apache Kafka with Confluent Schema Registry (Avro) and the transactional outbox pattern.
• Other Data Stores: Redis, MongoDB, Elasticsearch, and Amazon S3 (EU region).
• Build & Testing: Gradle 8 (Kotlin DSL), JUnit 5, Testcontainers, and contract tests for every event.
• DevOps & Observability: Docker, Helm, Kong API Gateway, Prometheus, Grafana, and OpenTelemetry.
• Full familiarity with every tool above is not expected on day one; strong Java, Spring Boot, and EVM fundamentals are required, and the remainder can be learned within the codebase.
Nice-to-Have Skills
• Experience with hexagonal (ports-and-adapters) architecture or Spring Modulith.
• Experience building multi-tenant SaaS platforms, particularly with PostgreSQL row-level security.
• Experience in regulated domains such as GDPR, supply chain traceability, GS1 standards, or sustainability reporting.
• Experience with event sourcing, sagas, and the transactional outbox pattern.
• Knowledge of Digital Product Passport (DPP) concepts and the EU ESPR framework.
• Hands-on production experience with Elasticsearch, jOOQ, or OpenTelemetry.
Additional Requirements
• Comfort with our delivery standard: one task, one branch, one merge request. A task is complete only when the full build passes, new tables have migrations, every new event has a contract test, and module-boundary tests still pass.
• Commitment to treating repository specification documents as the source of truth over informal agreements.
• Willingness to give and receive thorough code reviews covering both security and quality.
• Self-motivated and able to work through a detailed written backlog without close supervision.
• Strong documentation and technical writing skills.
What We Offer
✔ Fully Remote Position
✔ Flexible Working Hours
✔ Opportunity to work on regulated blockchain and sustainability solutions
✔ Exposure to Digital Product Passport (DPP), AI, and emerging technologies
✔ Career Growth Opportunities
✔ Collaborative International Team Environment
How to Apply
Please send your resume and relevant project portfolio to career@bangopure.com.
Subject Line: Application – Blockchain Engineer
Application Deadline: 30 September 2026
Only shortlisted candidates will be contacted.
Join BangoPure Limited and help build secure, verifiable, and compliant blockchain solutions that drive sustainability, traceability, and digital transformation worldwide.

Work arrangement
Yes