Senior Software Engineer

About Onyx.

Onyx is building the market for people who enjoy being right. Our consumer platform lets people take positions on what happens next across sports, prediction markets, crypto, financial markets, politics, culture, and real-world events.

More than one million users have already found Onyx. Now, we’re bringing that same energy into regulated financial markets through Onyx Predictions, a CFTC-registered introducing broker and NFA member.

In June 2026, we raised a $20 million Series A led by Payward, the parent company of Kraken, valuing Onyx at $220 million less than one year after emerging from beta. Our team comes from Jane Street, DraftKings, Robinhood, xAI, SIG, HRT, and Harvard.

We’re building Onyx in New York with a small team, serious momentum, and no interest in moving slowly. The product is live. The market is growing. The category is still ours to define.

The Role.

We’re hiring a Senior Software Engineer to shape and build the systems and consumer experiences at the center of Onyx. You’ll work across TypeScript, React, React Native, Node.js, PostgreSQL, and AWS, spanning customer-facing trading products, backend financial infrastructure, and real-time systems.

You’ll lead complex projects from initial design through production, set a high bar for architecture and execution, and help other engineers make good technical decisions. Your work will ship directly to users and support the systems that keep Onyx’s markets moving.

What You’ll Own:

• Lead design and delivery of full-stack features using TypeScript, React, React Native, and Node.js.
• Build backend services for markets, orders, execution, positions, balances, and settlement.
• Design APIs, real-time systems, and PostgreSQL workflows that preserve reliability and data consistency.
• Build and operate production services and infrastructure in AWS.
• Integrate with exchanges, liquidity providers, payment systems, and financial partners.
• Set technical direction for projects and improve system performance, observability, reliability, and fault tolerance.
• Work closely with product, design, trading, and operations from problem definition through launch.
• Raise the quality of engineering through design reviews, thoughtful feedback, and technical mentorship.
• Investigate difficult production issues and follow through on durable fixes.

You’ll Do Well Here If You:

• Have 5+ years of professional software engineering experience building production systems.
• Are highly proficient in TypeScript and Node.js, with experience building user-facing applications in React.
• Have production experience with PostgreSQL and AWS.
• Understand relational data modeling, transactions, concurrency, and consistency.
• Have built real-time, event-driven, or distributed systems.
• Can lead ambiguous, cross-functional projects and make sound architectural decisions.
• Communicate clearly and work effectively across engineering and non-engineering teams.
• Move quickly while maintaining a high bar for quality, reliability, and customer experience.

Even Better If You Have:

• Experience with React Native or Expo.
• Worked with WebSockets, live data feeds, streaming systems, or event-driven architectures.
• Built products in trading, crypto, payments, prediction markets, or consumer fintech.
• Experience with order management, execution, market data, settlement, or broker connectivity.
• Helped scale a consumer application through rapid growth.

Location:

• This role is based in our NoHo, Manhattan office, with core in-office days Tuesday through Thursday.
• Candidates must be authorized to work in the United States. Onyx is unable to provide employment sponsorship for this position.

Compensation and Benefits:

• The anticipated base salary range for this position is $175,000-$215,000, depending on experience, impact, and scope, plus a target bonus and equity. 

Benefits include:

• Fully covered medical, dental, and vision insurance.

• Meaningful equity ownership.

• Commuter benefits.

Why Onyx?

Onyx is for people with conviction.

We hire talented people, give them meaningful ownership, and expect them to use it. Our teams stay small, the work stays visible, and the distance between an idea and production stays short.

Onyx moves quickly because our markets move quickly. Titles matter less than judgment, initiative, and the quality of what you ship. Good ideas can come from anywhere, but the person willing to make the call is expected to follow it through.

We value people who are ambitious without ego, intellectually honest, comfortable with uncertainty, and energized by hard problems. We debate openly, decide quickly, and take responsibility for the result.

Come build what’s next with us.