Full-Stack Software Engineer New York, NY

You called it. Now help us build it.

Onyx is a prediction market for people who are tired of being right with nothing to show for it.

We’re building a platform where users can take positions on the outcomes they understand - from sports and crypto to culture, current events, and everything people already argue about online.

We’re a fast-growing, venture-backed team based in NoHo, with backgrounds from Jane Street, DraftKings, Robinhood, xAI, and Harvard. Through our exclusive partnership with Payward, the parent company of Kraken, we’re building the infrastructure behind the next generation of prediction markets.

The Opportunity

You’ll build across the Onyx platform - from the interfaces customers use to the backend systems handling markets, orders, positions, balances, and real-time data.

Our stack is primarily TypeScript, React, React Native, Node.js, PostgreSQL, and AWS. We operate like a small, high-output team: engineers own projects end to end, work closely with product, and ship directly to users. Some systems already exist. Others are still a blank page. Your work will be visible, your responsibilities will grow quickly, and you’ll have a meaningful voice in the product and architecture.

What You’ll Own

• Build and ship full-stack product features using TypeScript, React, and Node.js.
• Develop customer-facing trading experiences across web and mobile.
• Build backend services supporting markets, orders, execution, positions, balances, and settlement.
• Design reliable APIs and real-time data systems for live markets and pricing.
• Create scalable PostgreSQL schemas, queries, and transaction workflows.
• Build and maintain cloud infrastructure and production services in AWS.
• Integrate with exchanges, market makers, liquidity providers, payments systems, and external financial partners.
• Improve system performance, reliability, monitoring, and fault tolerance.
• Work closely with product, design, trading, and operations from idea through launch.
• Make technical decisions and own their outcomes.
• Ship quickly, learn from real usage, and keep improving the product.

You’ll Do Well Here If You

• Have 3+ years of professional software engineering experience.
• Are highly proficient in TypeScript, React, and Node.js.
• Have experience building and maintaining production applications end to end.
• Understand relational databases, transactions, and data consistency.
• Have worked with PostgreSQL and AWS in a production environment.
• Are comfortable building highly concurrent or real-time systems.
• Can move between frontend, backend, and infrastructure depending on what the product needs.
• Have led meaningful technical projects from planning through launch.
• Care about performance, reliability, and the customer experience.
• Can operate without a detailed playbook.
• Move quickly without treating quality as optional.

Even Better If You Have

• Experience with React Native or Expo.
• Built trading, brokerage, exchange, payments, or other financial technology.
• Worked with WebSockets, live data feeds, or event-driven systems.
• Experience with order management, trade execution, market data, or broker connectivity.
• Built products in prediction markets, sports, crypto, or fintech.
• Helped scale a consumer platform through rapid growth.
• Experience working directly with users or external partners.

How We Work

We hire talented people, give them meaningful ownership, and expect them to use it.

Onyx moves fast because the market moves fast. Titles matter less than judgment. Good ideas can come from anywhere, but ownership stays with the person willing to make the call and follow it through.

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 role.

Compensation and Benefits

The anticipated base salary range is $150,000–$200,000, depending on experience and scope. Compensation also includes equity and benefits.

Benefits include:

• Fully covered medical, dental, and vision insurance.
• Meaningful equity ownership.
• Daily lunch stipend.
• Dinner and transportation benefits when working late.
• Commuter benefits.
• Unlimited PTO.
• A front-row seat to building a new category.

Equal Opportunity

Onyx is an equal opportunity employer. We consider qualified applicants without regard to race, color, religion, sex, gender identity, sexual orientation, national origin, age, disability, veteran status, or any other characteristic protected by applicable law.