Senior Java Engineer; Hybrid, U.S Denver Metro

Senior Java Engineer
Denver, CO (Hybrid)

Fusion Auth is a fast‑growing startup and leading provider of customer identity and access management (CIAM) software headquartered in Denver, Colorado. Our mission is to make authentication and authorization simple and secure for every developer. Our product helps businesses securely manage customer identities and access, ensuring a seamless and safe user experience for some of the largest brands in the world.

We are committed to delivering exceptional value and satisfaction to our clients through top‑notch service and support. With a great team and strong investors, we are expanding our team to help accelerate our growth and take Fusion Auth to the next level.

We are recruiting a Senior Java Software Engineer who will join our engineering team to help us achieve these goals. This exciting role will allow you to build new features, extend existing features, learn from customers to improve the product and participate in our growing developer community. For this role, you must be a creative and quantitative thinker. You should be interested in the authentication, authorization and user management space.

You should be seasoned at writing secure and high‑performance code. The ideal candidate will be a self‑starter, fast worker and excited about growing a company from the ground up. This position reports to the Engineering Manager.

• Writing high‑quality, performant, and secure code
• Connect unfamiliar technical concepts to existing knowledge and find pragmatic paths forward
• Balance immediate deliverables with long‑term architectural thinking and planning
• Writing extensive and thorough tests
• Designing and producing new features
• Maintaining software with bug fixes and enhancements
• Writing clear, high‑quality documentation for new features
• Rotate as the on‑call engineer to solve critical customer issues; off‑hours support required as needed
• Provide technical support to customers
• Be a voice of positive change in the Engineering organization

Required

• 10+ years of professional software development experience
• Bachelor’s degree in computer science, or demonstrable experience with a broad set of theoretical topics
• Highly proficient in object‑oriented design and implementation
• Understanding of the full web stack (HTTP, TCP/IP, REST, etc)
• Experience building highly available, high‑performance, scalable applications
• Expertise in building multi‑threaded, API‑first applications
• In‑depth knowledge of unit and integration testing
• Real working knowledge of relational databases—query optimization, indexing strategies, database design beyond ORM abstractions
• Experience up and down the stack: cloud infrastructure, operating systems, databases, back‑end services, and JavaScript on the front end
• Comfortable working in a hybrid model (in‑office attendance expected 2 days/week for first 3‑6 weeks, then hybrid/remote as needed)

Preferred

• Strong quantitative and data‑driven approach to solving problems
• Quick learner with the ability to master new technologies and skills rapidly
• Interest or experience in the authentication space
• Influential communicator: holds strong opinions but adapts flexibly to new information or team input
• Appreciates first principles thinking, but understands when it’s time to stop theorizing and start building
• Comfortable and passionate about working in open‑source environments
• Adaptable to challenges common in a startup with ~50 employees
• Enjoys and thrives in a dynamic startup vibe

• $140 – 180k expected base salary range*

When you join Fusion Auth’s Denver team, you’ll enjoy a modern campus experience designed for productivity, wellness, and community:

• Newly upgraded amenity spaces including a sleek tenant lounge and café with booth seating and collaborative work spaces
• Access to a fitness studio, showers, lockers, and secure bike storage
• Regularly stocked in‑suite kitchen with a variety of snacks and beverages to keep you fueled throughout the day
• Onsite café offering chef‑driven menus with fresh, locally sourced, organic, and non‑GMO options to suit diverse dietary needs; easy ordering via app
• 3‑…