Blockchain Java Backend Developer
Must Have Technical/Functional Skills
Core Backend Skills
• Strong proficiency in Java (8+), and frameworks such as Spring Boot / Spring Cloud.
• Experience building distributed systems and microservices architectures at scale.
• Strong knowledge of:
o Concurrency, multithreading, asynchronous programming
o API design (REST/gRPC), security (OAuth2/JWT), and integration patterns
• Solid understanding of data stores:
o SQL (PostgreSQL/MySQL) and/or NoSQL (MongoDB/Cassandra)
o Caching (Redis) and search (Elasticsearch) is a plus
• Hands-on experience with message streaming/queues:
Blockchain Skills (Must-Have)
• Strong understanding of blockchain fundamentals:
o Transactions, blocks, confirmations/finality, consensus, gas/fees, wallets, keys.
• Experience integrating backend services with blockchain networks/nodes:
o Ethereum-compatible networks (Ethereum/Polygon/BSC) using Web3j, ethers-style approaches
o and/or permissioned chains (Hyperledger Fabric, Corda, Quorum)
• Experience supporting large blockchain deployments:
o Node connectivity, RPC management, event indexing, chain reorg handling, retry strategies.
DevOps / Cloud (Preferred)
• Experience with Docker and Kubernetes for containerized microservices deployments.
• CI/CD exposure (Jenkins/GitHub Actions/GitLab CI/Azure DevOps).
• Cloud experience (Azure/AWS/GCP) is a plus.
• Understanding of security practices:
o Secrets management (Vault/KMS), TLS, RBAC, network security.
Roles & Responsibilities
• Design and develop Java-based backend services that interact with blockchain networks and nodes (public or permissioned).
• Build and scale microservices-based architecture supporting blockchain transaction workflows, event processing, and off-chain components.
• Develop reliable services for:
o Transaction orchestration
o Smart contract invocation
o Blockchain event subscription/listening
o On-chain/off-chain data synchronization
• Implement scalable APIs (REST/gRPC) for blockchain-enabled products and integrations.
• Optimize performance for high throughput and low latency:
o Transaction throughput handling, batching, retries, idempotency, rate limiting.
• Ensure secure integration with blockchain:
o Key management best practices, signing transactions, secure secret handling.
• Implement observability and reliability standards:
o Logging, monitoring, tracing, alerting, SLOs/SLAs.
• Work with DevOps/SRE teams to support production deployments, incident triage, and capacity planning.
• Contribute to architecture decisions including:
o Event-driven architecture (Kafka/RabbitMQ), caching strategies, database selection, and deployment topologies.
Salary Range- $100,000-$130,000 a year
