Senior Full-Stack Engineer: GraphQL, React & Scale

PENN Interactive; United States; On-site; USD 135,000 - 180,000; Full time

Benefits offered by this job

Education and conference reimbursem

Career progression and mentoring

Job summary

PENN Interactive is hiring a senior software engineer in the United States to build and evolve GraphQL schemas, server-driven UI contracts, and scalable APIs across iOS, Android, and web clients. You will work with React and TypeScript to deliver fast, accessible experiences and partner with product/design on customer features.

You will also design monitoring and testing pipelines, own release cycles, and contribute to production reliability while mentoring teammates and driving architectural

Qualifications

• 5+ years of experience in software engineering.
• Strong JavaScript, TypeScript, and React, with real UX instincts.
• 2+ years designing and evolving GraphQL schemas for multi-client surfaces (iOS/Android/web).
• Fluency with HTML, CSS, and browser environment (DOM, platform APIs).
• Solid CS foundation: data structures, distributed systems, algorithms, software design.
• Experience with API development in Node or Bun, or similar server framework.
• Experience with Kubernetes and containers.
• On-call rotation experience and end-to-end release ownership.
• Clear writing; authored tech specs, runbooks, and design docs.
• Experience with testing frameworks: Jest or Vitest, and ExUnit/RSpec/pytest.
• Nice to have: Apollo Federation at scale, GraphQL APIs with Absinthe, mobile development, hexagonal architecture, domain-driven design, relational DBs.

Responsibilities

• Design and evolve GraphQL schemas in a federated graph for client surfaces.
• Develop, scale, and optimize GraphQL APIs, RPC endpoints, and SQL queries behind our web surfaces.
• Build front-end applications and shared libraries with React and TypeScript.
• Partner with product and design to architect and ship customer-facing features.
• Use observability tooling to diagnose issues and improve guest experience.
• Set up monitoring and alerting in DataDog for owned systems.
• Improve code quality by addressing technical debt and enforcing standards.
• Mentor teammates through code reviews and pairing.
• Write thorough tests and strengthen automated pipelines with QA.

Skills

JavaScript

TypeScript

React

GraphQL

Server-side APIs

Kubernetes

Testing frameworks

Git / GitHub

Tools

Node or Bun

Apollo Federation

CI/CD

SQL

DataDog

Job description

PENN Interactive is hiring a senior software engineer in the United States to build and evolve GraphQL schemas, server-driven UI contracts, and scalable APIs across iOS, Android, and web clients. You will work with React and TypeScript to deliver fast, accessible experiences and partner with product/design on customer features.

You will also design monitoring and testing pipelines, own release cycles, and contribute to production reliability while mentoring teammates and driving architectural