Full Stack Engineer

About the COOL company

At the COOL company, we believe in creating a win-win environment where everyone benefits. We are committed to ensuring users, publishers, franchisees, and advertisers all have a better experience and achieve more than they ever thought possible through our innovation, advanced AI, groundbreaking advertising technology, and teams of inspired experts. Our every move, expansion, acquisition, and upgrade is done to provide that better experience for an ever-growing list of satisfied clients and users all over the world.  

COOL Media products under the COOL company include DCO & Creative Automation, a data-driven, creative ad server capable of personalizing, automating, measuring, and optimizing digital ads and placements for advertisers; Franchise & Multi-Location, a complete advertising management platform for franchise and network businesses; Media & Attribution, a managed service solution for agencies and brands to reach and measure audiences; Publisher Experiences, a premier SSP and engagement platform for publishers; and Supply-Side Platform, delivering website and app publishers everything they need to maximize their ad revenue.

Coming soon in 2026, COOL AI is a next-generation advertising platform that builds, buys, and optimizes digital ad campaigns faster and smarter using AI. It automates every step of the media journey—from generating ad creatives to launching campaigns and optimizing performance across channels like Google and Facebook. With no agency fees or waiting, COOL AI helps brands maximize ROI through data-driven strategy, automated creative generation, and real-time performance measurement.

Collectively, the COOL company reaches over 350 million consumers monthly across their network of premium publishers and advertisers, including Disney, Hyundai, Air France, Kohler, Suzuki, Acer, Pearle Vision, Trek, Brita, Viking Cruises, MLB, Playmaker, Blitz, Evolve Media, and more.  Under the former umbrella of Insticator, the COOL company is a proud 7x recipient of the Inc 5000 list of America's fastest-growing private companies, a 2x recipient of Deloitte's Fast 500, recognized on Crain's New York Fast 50 list, recognized by Digiday's Digiday Media Awards as a company working to modernize digital media, and awarded as one of AdWeek's Top 10 Fastest Growing Solution Providers globally.

Our Core Values

At the COOL company, we believe in being C.O.O.L.:

Creative - we look to find solutions that others can’t and new ways of doing things that are smarter, faster, better and more efficient.

Open-minded - we’re always evolving and keep an open mind as to new ways of doing things, new solutions and new processes that can help us.

Optimistic - The glass is always half full :) as a growing tech startup we’re always faced with new challenges, we overcome them because we see them as opportunities.

Leaders - We look for drivers, people who like to set the pace of the organization, who don’t simply go with the flow, you’re setting a fast impact pace and holding others to it.  We look for speed, impact, and setting the industry benchmark.

We creatively integrate new elements in innovative combinations, fueled by our optimism to drive success. Our open-mindedness allows us to embrace new ideas and approaches, empowering us to lead our industry through bold initiatives. That’s the attitude we bring to work with us every day, and it’s what we expect from everyone who works here.

That’s just part of the values that drive us to greatness. We also believe in this trio of truths that inform every decision we make and everything we do:

• Sleeves Up: At the COOL company, we provide you with the autonomy and creativity needed to own your role. We encourage iteration where necessary so that you can drive massive impact.
• 100% Viewability: the COOL company is passionate about open feedback at all levels of the company. This allows us to fail fast, create in real-time, and build an open company culture.
• Be Defiantly Great: We're defiant, and that's in our blood. Challenging the status quo is a central part of who we are. We're capable of much more than what others deem impossible.

About the Role

We are looking for a Mid-Senior Full-Stack Engineer to join our Product Engineering team, reporting to the Engineering Manager (Bi Yoo). This role is responsible for building and maintaining the web applications that power our advertising platform, including the Cool AI campaign management system, billing and invoicing module, and advertiser-facing dashboards. The Full-Stack Engineer will work across our frontend (React/TypeScript) and backend (Java/Spring Boot) stack, delivering features end-to-end from database schema design through API development to polished UI implementation.

Challenges and Opportunities

 This role spans the full product surface of a growing ad tech platform. You'll build features that advertisers interact with daily — campaign creation and launch workflows, real-time performance dashboards, multi-platform account

  integrations (Google Ads, Meta, Adform), and automated billing systems. There is significant opportunity to shape product architecture as we scale to support new advertising channels, expand our AI-driven campaign optimization, and

  onboard enterprise clients with complex billing and permissions requirements.

Responsibilities and Duties

•  Design and implement full-stack features across React (TypeScript, Tailwind CSS, Vite) and Spring Boot (Java 17, PostgreSQL) codebases
• Build and maintain RESTful APIs with proper authentication, authorization (role-based access control), and input validation
• Design and evolve PostgreSQL database schemas using Flyway migrations, including JSONB modeling for flexible domain objects
• Develop responsive, accessible UI components following existing design patterns and component libraries
• Integrate with third-party advertising platform APIs (Google Ads, Meta Marketing API, Adform) for account management and data synchronization
• Implement and maintain OAuth flows for external platform connections
• Build complex business logic including billing calculations, invoice generation, and payment processing workflows
• Write efficient database queries and optimize application performance for large datasets
• Collaborate with the data engineering team on Snowflake integrations for analytics and reporting features
• Participate in code reviews, providing constructive feedback and maintaining code quality standards
• Troubleshoot production issues across the full stack using AWS CloudWatch logs and application monitoring
• Contribute to CI/CD pipeline maintenance and deployment processes
  

Qualifications

Professional Competencies

• 4-6 years of professional software engineering experience in full-stack web development
• Strong proficiency in Java (11+) and Spring Boot, including Spring Security, Spring Data JPA, and RESTful API design
• Strong proficiency in React (16+) with TypeScript, including hooks, state management, and modern component patterns
• Solid experience with PostgreSQL including schema design, query optimization, indexing strategies, and migrations
• Experience with CSS frameworks (Tailwind CSS preferred) and building responsive layouts
• Familiarity with cloud services, particularly AWS (S3, SES, Lambda, ECS, CloudWatch)
• Experience integrating with third-party REST APIs and OAuth 2.0 authentication flows
• Understanding of Git workflows, pull request processes, and collaborative development practices
• Ability to independently own features from technical design through deployment
• Strong debugging skills across frontend and backend, including browser DevTools and server-side logging
  

Cultural Competencies

• Must be able to work primarily between the hours of 9:30 AM - 6:30 PM ET
• Must have a player/coach mentality, willing to both execute and lead
• Ability to juggle multiple projects concurrently and set and meet deadlines
• Skilled at receiving and providing direct feedback
• Collaborative mindset and great teamwork skills
• Entrepreneurial & adaptable; great learning skills
• Curious, research-minded, data-informed
• Able to search for possible solutions and apply them
• Creative confidence
• Proactive communicator
• A sense of humor and a love of online culture
• Thrives in a start-up culture