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.