• Design and build blockchain integration services — transaction signing, deposit processing, and confirmation tracking — across multiple networks (EVM, Solana, Polkadot, XRP, and others) • Build and maintain gRPC microservices in Go within an event-driven architecture using NATS JetStream • Implement transaction state machines with reliability guarantees including idempotency, distributed locking, and chain reorganization handling • Integrate with custody providers for secure transaction signing and wallet management • Monitor blockchain networks for deposits, confirmations, and anomalies • Participate in on-call rotation, responding to production incidents across blockchain infrastructure • When necessary, communicate directly with client technical teams

• Read, understand, and write code and unit tests (primarily in Java) • Investigate, diagnose, and implement improvements for performance bottlenecks and cost inefficiencies • Implement, test, and deploy architecture and library changes which enable new insights and understanding, including cost modeling/reporting and data patterns • Respond to performance and reliability issues identified internally and by customers • Collaborate with other backend engineers to solve a broad range of distributed systems problems

Role Description zerohash is looking for a Senior Blockchain Engineer to help architect and build the infrastructure that powers digital asset transactions across multiple blockchain networks. We are a high-performing team looking for an equally ambitious and driven teammate. The right candidate for this position is detail-oriented, deeply technical, and driven. You are eager to learn new technologies and complex systems. You build resiliency and scalability into the platform at every step. If you're looking to have a massive impact in one of the most exciting markets in decades, you will find this role challenging and rewarding in equal measure. Key Responsibilities - Design and build blockchain integration services — transaction signing, deposit processing, and confirmation tracking — across multiple networks (EVM, Solana, Polkadot, XRP, and others) - Build and maintain gRPC microservices in Go within an event-driven architecture using NATS JetStream - Implement transaction state machines with reliability guarantees including idempotency, distributed locking, and chain reorganization handling - Integrate with custody providers for secure transaction signing and wallet management - Monitor blockchain networks for deposits, confirmations, and anomalies - Participate in on-call rotation, responding to production incidents across blockchain infrastructure - When necessary, communicate directly with client technical teams Qualifications - 5+ years of software engineering experience, preferably in the FinTech space - Deep proficiency with Go - Understanding of blockchain technologies, protocols, and their applications - Experience with gRPC and Protocol Buffers - Familiarity with message brokers or event streaming systems (NATS, Kafka, or similar) - Experience with MongoDB or other document databases - Understanding of SQL and relational database schema design - A humble and scrappy get-it-done mindset; you're resourceful and in your element going from 0 to 1 - Excellent problem solving skills — can troubleshoot complex distributed systems - Comfort with ambiguity; the ability to independently lay out and test clear hypotheses and solve problems without well-defined direction - Excellent verbal and written communication skills Preferred - Bachelor's in computer science or equivalent experience - Experience at a banking-as-a-service, brokerage-as-a-service, or payment-as-a-service business - Experience with digital assets or centralized exchanges - Experience integrating with blockchain custody platforms (Fireblocks, BitGo, or similar) - Experience with distributed systems patterns (distributed locking, idempotency, state machines, CQRS) - Experience with smart contracts - Familiarity with Kubernetes and observability tooling (Prometheus, Grafana, OpenTelemetry) Company Description zerohash is the leading crypto and stablecoin infrastructure platform and the operating system for digital money, powering the next generation of financial services. Founded in 2017, zerohash enables banks, brokerages, fintechs, and payment companies to offer crypto trading, stablecoin payments, and tokenized assets without having to build or manage complex blockchain infrastructure on their own. - The zerohash platform supports three core pillars: Trade, Transact, and Tokenize. - Through a single integration, customers can launch regulated crypto buy, sell, and custody services; enable 24/7 stablecoin-based funding, payouts, and settlement; and issue and manage tokenized assets with built-in compliance, risk controls, and reporting. - zerohash is trusted by some of the world's most recognized financial and consumer brands. - The company is deeply regulated and compliance-first, operating across the U.S. and internationally. - zerohash has raised over $280 million in funding from a mix of leading venture firms and strategic investors. - zerohash has been featured in top-tier media outlets and its leadership team regularly contributes to global conversations on the future of payments, investing, and financial infrastructure. The zerohash Culture - Independence/Ownership - An ability to work autonomously. - Passion - We are innovating quickly and challenging the status quo. - Collaborative - A good attitude and respect for others. - Initiative - An ability and passion for learning and asking questions. - Empathy - An ability to listen, respect, and understand your co-workers, customers, and everyone you interact with. - Adaptability - An ability to respond quickly. - Transparency - We believe that transparency is critical to empowering everyone to make the best decisions. - Integrity - Integrity creates trust.

• Architect, design, and guide the implementation of Layer 1 and Layer 2 blockchain protocols tailored for AI-driven workloads. • Define the technical roadmap and ensure architectural alignment with business objectives. • Create and maintain technical documentation, design specifications, and architectural blueprints. • Mentor and support engineering teams in building EVM-compatible and non-EVM blockchain platforms. • Ensure enterprise-grade security, scalability, and fault tolerance across blockchain and AI pipelines. • Mentor and guide development teams on blockchain best practices, patterns, and standards. • Conduct code reviews and architecture reviews to ensure quality, reliability, and maintainability. • Stay current with emerging blockchain technologies, standards, and implementation practices to ensure long-term platform relevance.