Senior API Engineer - Polymarket US

Polymarket•New York, NY

About The Position

Polymarket is looking for an experienced API engineer to develop and deploy endpoints for our ISV customers. You'll build the critical systems that facilitate access to our CFTC-regulated exchange, working directly on REST and FIX API systems. This is a high-impact role where you'll work directly with engineering teams, build systems that handle liquidity at scale, and help establish the technical foundation for our growing US Exchange business.

Requirements

3-10 years of professional software development experience
Strong FIX / REST / SDK experience with direct previous projects
Solid experience with AWS, Cloudfare, Kubernetes, Kafka
Experience building data-heavy applications or tools
Strong collaboration and communication skills—you work well with non-technical stakeholders
Bias for action—all-in work mindset eager to work immediately on solving problems
Builder's mindset—you take pride in creating tools that solve real operational problems

Nice To Haves

Background in fintech, payments, reconciliation systems, or regulated environments
Understanding of regulated exchange backend and audit requirements
Bachelor's degree in Computer Science or equivalent

Responsibilities

Maintain API access to our US Exchange.
Create systems that help ISV participants and institutional customers set market prices on the US Exchange.
Oversee Onboarding of Market Makers.
Partner closely with our growing Forward Deployed Engineering team to help market makers access the API.
Manage FIX / REST / SDK Integrations.
Architect and test systems for handling various institutional customers and access needs.
Design for scale and compliance.
Build systems that handle thousands of daily transactions while maintaining audit trails and meeting CFTC regulatory requirements.
Collaborate with internal teams.
Partner closely with operations, compliance, and product to understand workflows, gather feedback, and iterate quickly on tooling.
Lead technical decisions.
Participate in architecture discussions, code reviews, and help establish best practices for the team.