Blockchain Java Backend Developer

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:
  • Concurrency, multithreading, asynchronous programming
  • API design (REST/gRPC), security (OAuth2/JWT), and integration patterns
• Solid understanding of data stores:
  • SQL (PostgreSQL/MySQL) and/or NoSQL (MongoDB/Cassandra)
  • Caching (Redis) and search (Elasticsearch) is a plus
• Hands-on experience with message streaming/queues:

Blockchain Skills (Must-Have)

• Strong understanding of blockchain fundamentals:
  • Transactions, blocks, confirmations/finality, consensus, gas/fees, wallets, keys.
• Experience integrating backend services with blockchain networks/nodes:
  • Ethereum-compatible networks (Ethereum/Polygon/BSC) using Web3j, ethers-style approaches
  • and/or permissioned chains (Hyperledger Fabric, Corda, Quorum)
• Experience supporting large blockchain deployments:
  • 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:
  • 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:
  • Transaction orchestration
  • Smart contract invocation
  • Blockchain event subscription/listening
  • 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:
  • Transaction throughput handling, batching, retries, idempotency, rate limiting.
• Ensure secure integration with blockchain:
  • Key management best practices, signing transactions, secure secret handling.
• Implement observability and reliability standards:
  • 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:
  • Event-driven architecture (Kafka/RabbitMQ), caching strategies, database selection, and deployment topologies.

Salary Range

$100,000-$130,000 a year

Qualifications

BACHELOR OF COMPUTER SCIENCE