Senior Backend Engineer, Product Infrastructure

About the role

Polymarket is looking for a senior backend engineer to take ownership of the core APIs and data models that power our consumer-facing platform. In this role, you will be responsible for designing, developing, and maintaining the foundational infrastructure that supports our fast-growing prediction market platform. You will work at the intersection of backend infrastructure and product development, building primitives that frontend, mobile, and product teams rely on to deliver features to users. This position offers a high level of ownership, requiring strong execution skills and the ability to balance technical improvements with rapid delivery. As part of our engineering team, you will contribute to scaling our systems to handle increasing volume and complexity, ensuring reliability and performance for millions of users.

Key facts

What you'll do

• Design, build, and evolve core domain APIs and data models that underpin Polymarket's consumer product, ensuring they are scalable, reliable, and maintainable.
• Develop real-time infrastructure components, including gRPC/Connect services, to support low-latency, high-throughput data streaming and communication.
• Lead efforts to migrate and improve real-time streaming systems, such as WebSocket-to-gRPC-stream migrations, to enhance performance and developer experience.
• Collaborate closely with frontend, mobile, and product teams to deliver end-user features like personalization, search capabilities, and live data feeds that enhance user engagement.
• Unify fragmented systems and APIs by consolidating services into cleaner, reusable primitives, which will accelerate future feature development and reduce technical debt.
• Balance the need for technical debt cleanup with the delivery of new features, often under tight deadlines, maintaining a pragmatic approach to engineering challenges.
• Work cross-functionally with engineers from infrastructure and data teams to ensure integration of backend systems with the broader platform.
• Develop event-driven and notification infrastructure to support real-time updates and alerts for users.
• Contribute to the evolution of the platform's backend infrastructure, focusing on scalability, reliability, and security.
• Participate in code reviews, system design discussions, and documentation efforts to promote best practices and knowledge sharing across the team.
• Continuously improve system performance and robustness through monitoring, testing, and iterative development.
• Support deployment, monitoring, and troubleshooting of backend systems in cloud environments, ensuring high availability and uptime.
• Engage in planning and estimation for upcoming projects, providing technical guidance and mentorship to junior engineers when appropriate.
• Stay informed about emerging backend technologies and industry best practices, evaluating their applicability to Polymarket's infrastructure needs.

Requirements

• Proven experience designing and evolving APIs and data models for consumer-facing products at scale.
• Hands-on experience with gRPC/Connect and real-time streaming technologies, including building and maintaining streaming services.
• Experience with WebSocket-to-gRPC-stream migrations or similar real-time communication system improvements.
• Demonstrated ability to partner directly with frontend, mobile, and product teams to ship features that impact end users.
• Strong background in unifying fragmented services and APIs into cleaner, reusable primitives to improve system maintainability.
• Pragmatic judgment in balancing technical debt cleanup with delivering new features, especially under P0 deadlines.
• Experience working at a high-growth consumer product company or marketplace is a plus.
• Familiarity with deploying and managing systems in cloud environments such as AWS or GCP.
• Knowledge of containerization technologies and best practices for cloud deployment.
• Strong problem-solving skills and the ability to work independently and collaboratively in a fast-paced environment.
• Excellent communication skills, with the ability to clearly articulate technical concepts to non-technical stakeholders.
• A proactive attitude towards learning new technologies and improving existing systems.

Nice to have

• Experience with cloud deployment and infrastructure management in AWS or GCP.
• Background working on high-traffic, scalable systems in a marketplace or prediction platform.
• Familiarity with container orchestration tools like Kubernetes.
• Experience with CI/CD pipelines and automation tools.
• Knowledge of security best practices for cloud infrastructure and APIs.
• Prior involvement in open-source projects or contributions to developer communities.

Skills & tools

• Express
• AWS
• GCP
• gRPC
• WebSocket
• Cloud deployment and containerization (preferred)
• API design and development
• Real-time streaming systems
• Event-driven architecture
• Monitoring and logging tools

Practical notes

an on-site role based in New York. Candidates should have experience working with cloud environments such as AWS or GCP and be comfortable deploying and managing scalable backend systems. The role involves building real-time infrastructure components and APIs that serve millions of users, with a focus on performance, reliability, and security. You will work closely with cross-functional teams including frontend, mobile, infrastructure, and data engineers to deliver impactful features and improvements. The environment is fast-paced, with an emphasis on shipping high-quality code under tight deadlines, balancing technical debt management with feature development. Candidates should be proactive, collaborative, and eager to stay current with emerging backend technologies to help Polymarket maintain its position as a leading prediction market platform.