Seasonal Java Swing Developer Jobs in Ridgefield Park, NJ

Launched in 2021, Fanatics Betting and Gaming is the online and retail sports betting subsidiary of Fanatics, a global digital sports platform. The Fanatics Sportsbook is available to 95% of the addressable online sports bettor market in the U.S. Fanatics Casino is currently available online in Michigan, New Jersey, Pennsylvania and West Virginia. Fanatics Betting and Gaming operates twenty-two retail sports betting locations, including the only sportsbook inside an NFL stadium at Northwest Stadium. Fanatics Betting and Gaming is headquartered in New York with offices in Denver, Leeds and Dublin.

Fanatics Markets is the real-money prediction and trading app where you can invest in moments you care about. Built on a secure platform, we let users predict real-world outcomes and trade on events they actually follow - from sports and entertainment to political elections and beyond. Our mission is to redefine how fans engage with the moments and markets that matter most. We're looking for the right people to help us build the future of prediction markets.

The Opportunity

As a Staff Engineer on our Distributed Systems team, you'll be at the core of what makes Fanatics Markets work - the event-driven infrastructure that powers real-money trading at scale. This is a hands-on, high-ownership role on a sprint-based team, where you'll work alongside our engineer leaders to build the systems that keep our markets liquid and our book healthy at peak volume. Real money is on the line every time our system quotes a price - the work is technically demanding, commercially consequential, and directly visible in daily P&L snapshots the whole team sees.

You won't be handed a spec. You'll be expected to understand the trading business well enough to write one, and to care about outcomes beyond just shipping the feature.

Responsibilities

• Design, build, and scale distributed systems using Kotlin, Java, and Spring Boot, architecting for the traffic spikes and concurrency demands of a live real-money trading platform.
• Own the development and optimization of high-throughput event pipelines using Kafka, including partition strategy, consumer group design, and exactly-once processing guarantees.
• Design and build systems that process high-throughput, low-latency event streams - ensuring data integrity, cache coherence, and sub-millisecond read paths under peak load.
• Partner with product and engineering leadership to align cross-domain technical decisions, contributing domain expertise while preserving architectural integrity
• Diagnose and durably fix production issues in a live trading environment, distinguishing pricing latency, strategy misfires, mapping errors, and adverse selection patterns
• Proactively identify performance bottlenecks and technical risk before they affect trading operations
• Raise engineering standards through design docs, code/architecture reviews, and patterns that scale as product expands

Qualifications

• 7+ years building scalable, fault-tolerant distributed systems in production
• Expert-level proficiency in Java or Kotlin and Spring Boot, with a strong command of modern API design - REST, gRPC, and Protobuf.
• Deep hands-on experience with Kafka (or Redpanda/Pub Sub) - including internal mechanics, partition strategies, consumer group rebalancing, and delivery guarantees.
• Deep experience with event-driven architecture and async messaging - consumer group strategies, partition schemes, delivery guarantees under real production load
• Demonstrated end-to-end domain ownership - designed, built, operated, and improved systems, not just shipped features
• Strong performance instincts - latency, throughput, and data pipeline efficiency, with a track record of measuring what matters
• Clear, direct communicator - comfortable writing a design doc, explaining a production failure to a trader, or debating trade-offs with a principal engineer
• High tolerance for ambiguity and speed - comfortable deploying daily and making good calls while the spec is still being written.

Preferred

• Experience with real-time delivery systems - WebSocket fan-out, server-sent events, or pub/sub at scale.
• Familiarity with financial platforms, real-time trading systems, or prediction markets.
• Experience in a high-growth startup environment where ownership is broad and the technical landscape evolves quickly.
• Familiarity with FIX protocol or exchange connectivity patterns.

Depending on the role, your interview and onboarding experience may include in-person components, such as onsite interviews or Launching into Better: LIVE-a multi-day cultural immersion in New York City for full-time, non-seasonal hires. These sessions are designed to build connection and bring our culture to life, though specific travel and participation requirements will be confirmed based on your role and location. Your recruiter will provide clear guidance at each stage of the process.

For information about our benefits, please visit https://benefitsatfanatics.com/

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