Founding Engineer, Frontend

Sarsfield Group; New York (NY); On-site; USD 175,000 - 225,000; Full time

Benefits offered by this job

Health coverage

Expensed lunches

Laptop and desktop provided

Job summary

Sarsfield Group is hiring its first frontend engineer for an on-site role in New York City. You will own the consumer web trading platform, shipping polished UI with real-time data and performance in mind.

You'll collaborate directly with the founders to shape the product roadmap, drive frontend architecture, and deliver fast, intuitive experiences with on-chain features. Equity and competitive salary reflect early-stage founding status.

Qualifications

• 2 to 8 years of frontend engineering experience.
• A track record of shipping polished consumer web applications.
• Deep understanding of performance, reliability, and complex application state.
• Comfort working in a small, fast-moving team alongside founders from Apple, Google, and leading crypto firms.
• Strong product judgment: not just how things look, but how they work and feel in a user’s hands.

Responsibilities

• Own and lead development of the company’s consumer web trading platform.
• Build fast, intuitive trading and portfolio experiences that make onchain settlement invisible to sports fans.
• Work directly with the two cofounders, a former crypto VC partner and product manager and a former Big Tech tech lead, to shape the product and technical roadmap.
• Drive frontend architecture decisions across a service-based stack, managing complex application state and real-time data flows.
• Help design APIs and transaction flows that bridge blockchain infrastructure and a seamless user experience.
• Help set a culture of high ownership and velocity as a true founding team member.

Skills

Frontend engineering

Performance optimization

Real-time data handling

Product judgment

Job description

A seed-stage consumer trading startup in New York City is hiring its first frontend engineer, with a $175K to $225K base and 1 to 2% founding equity.

Type: Full-time

Location: On-site, New York City

Experience: 2 to 8 years of frontend engineering

Base salary: $175K to $225K, depending on experience

Equity: 1 to 2% (founding engineer equity)

About the company

The company is building an exchange where sports fans can invest in the performance of individual professional athletes and trade 24/7, all season long. Unlike single-game player props or fantasy roster management, fans hold positions in players over time.

The team is 4 people, founded in 2025, with backgrounds at Apple, Google, Microsoft, and startups that built leading trading platforms. They have raised $4.1M in seed funding from top-tier crypto investors who were early backers of leading prediction markets.

What you’ll do

Own and lead development of the company’s consumer web trading platform.

Build fast, intuitive trading and portfolio experiences that make onchain settlement invisible to sports fans.

Work directly with the two cofounders, a former crypto VC partner and product manager and a former Big Tech tech lead, to shape the product and technical roadmap.

Drive frontend architecture decisions across a service-based stack, managing complex application state and real-time data flows.

Help design APIs and transaction flows that bridge blockchain infrastructure and a seamless user experience.

Help set a culture of high ownership and velocity as a true founding team member.

What we’re looking for

2 to 8 years of frontend engineering experience.

A track record of shipping polished consumer web applications.

Deep understanding of performance, reliability, and complex application state.

Comfort working in a small, fast-moving team alongside founders from Apple, Google, and leading crypto firms.

Strong product judgment: not just how things look, but how they work and feel in a user’s hands.

Bonus points

experience building trading products, fintech platforms, or anything with real-time data and charts.

Compensation and benefits

Base salary of $175,000 to $225,000, depending on experience.

1 to 2% equity. This is true founding engineer equity, a significant ownership stake that reflects the company’s early stage and the importance of this hire.

Health coverage.

Expensed lunches.

Laptop and desktop provided.

Location and work authorization

On-site in Manhattan, with a strong preference for 4 to 5 days per week in the office.

Flexible hours. This is not a strict 9am team, so coming in at 11 and staying late is fine.

Candidates already based in New York City or the surrounding area are preferred. Relocation support may be considered case by case for candidates specifically targeting a move to NYC.

Open to visa transfers, such as OPT and H1B transfers.