Senior Software Engineer, Onboarding (opens in a new tab)

At Justworks, you’ll enjoy a welcoming and casual environment, great benefits, wellness program offerings, company retreats, and the ability to interact with and learn from leaders in the startup community.

We’re helping businesses get off the ground by enabling them to focus on running their business. We solve HR issues. We’re data-driven and never stop iterating. If you’d like to work in a supportive, entrepreneurial environment, are interested in building something meaningful and having fun while doing it, we’d love to hear from you.

We're united by shared goals and shared motivations at Justworks. These are best summed up in our company values, which are reflected in our product and in our team.

If this sounds like you, you’ll fit right in.

Who You Are

Are you passionate about system design and development? Do you have experience building, deploying, and maintaining large‑scale, distributed applications? Are you ready to take your skills to the next level and join a team of innovative self‑starters in a supportive, entrepreneurial environment?

As a Senior Software Engineer, you will be leveraging your experience working within a service‑oriented architecture. You will be responsible for separating data and functionality as necessary, and will demonstrate an understanding and use of automated testing as a productivity multiplier. You are eager to learn and passionate about improvement. You want to understand how systems work, and you think about how to make them work even better. You will work closely with product managers, designers and other engineers to scope, design, and build new features and functionality. You will be working primarily on backend systems. We’re currently using Ruby on Rails as our main language, but prior experience in RoR is not a requirement.

Your Success Profile

What You Will Work On

The Onboarding teams transform a weeks‑long, support‑heavy onboarding process into a fully self‑serve experience, leveraging AI‑powered data ingestion and real‑time validation to take companies from signed contract to running payroll in a matter of days. A core part of this work is unifying how people join Justworks — today, full‑time, contractor, and international hires across PEO, ASO, and EOR each follow entirely different flows, and this role brings them all into one. Ultimately, this is about building the first product experience every new customer has. If onboarding feels hard, nothing else matters — making this role a direct driver of activation rate, time‑to‑first‑payroll, and onboarding completion.

• Collaborate with a cross functional team to design a next‑generation platform to unlock new business capabilities
• Take ownership of designing and implementing APIs, systems integrations and backend services
• Promote engineering excellence through technical leadership, knowledge‑sharing and mentorship
• Instate best‑practices observability and monitoring as “first principles” of all our services
• Keep extremely sensitive data compartmentalized and secure
• Perform other related duties as assigned

How You Will Do Your Work

As a Senior Software Engineer, how results are achieved is paramount for your success and ultimately result in our success as an organization. In this role, your foundational knowledge, skills, abilities and personal attributes are anchored in the following competencies:

• Good judgment – the exercise of critical thinking, analyzing and assessing problems and implications, identifying patterns, making connections of underlying issues, understanding risks and developing mitigation strategies, and taking ownership of the outcome.
• Resourcefulness – taking a can‑do approach, even in the face of obstacles and constraints by assessing what’s in front of you and effectively and efficiently optimizing what you have, whether it’s working on something new or thinking about how to do something better.
• Teamwork and communication – putting our collective best together through documentation, collaboration, relationship‑building, listening, empathy, recruiting, and evangelism.
• Influence and leadership – fostering a community of knowledge‑sharing, collaboration, mentorship, and forward‑thinking.
• Skills and knowledge – the capacity to actively learn and apply specific domain knowledge, know‑how, and best practices to continually enhance and improve.

In addition, all Justworkers focus on aligning their behaviors to our core values known as COGIS. It stands for:

• Camaraderie – Day to day you can be seen working together toward a higher purpose. You like to have fun. You’re an active listener, treat people respectfully, and have a strong desire to know and help others.
• Openness – Your default is to be open. You're willing to share information, understand other perspectives, and consider new possibilities. You’re curious, ask open questions, and are receptive to thoughts and feedback from others.
• Grit – You demonstrate grit by having the courage to commit and persevere. You’re committed, earnest, and dive in to get the job done well with a positive attitude.
• Integrity – Simply put, do what you say and say what you’ll do. You’re honest and forthright, have a strong moral compass, and strive to match your words with your actions while leading by example.
• Simplicity – Be like Einstein: “Everything should be made as simple as possible, but no simpler.”

Qualifications

• Minimum of 6 years of professional hands‑on experience
• Expertise in backend systems
• Strong object‑oriented design and coding skills
• Strong understanding of data structures and algorithms
• Experience modeling complex real‑world problems with robust data models and systems
• Experience supporting other engineers and acting as a “tech lead”
• Experience using Agile/Scrum methodology in a fast‑paced environment
• Experience in a high‑growth environment working with deadlines and milestones

Technologies Used:

• Messaging / APIs: Kafka, GraphQL, Apollo, Redis

The base wage range for this position based in our New York City Office is targeted at $167,500.00 to $205,000.00 per year.

Justworks Flex‑Work Model

Justworks believes in a flex‑work model where teammates have at least two days a week when they are expected to work in a global office. The exact schedule is at individual teams’ discretion.

Diversity At Justworks

Justworks is committed to maintaining a workplace where diversity of identity, culture, and life experience is the norm and is celebrated authentically and respected consistently. Diversity in our work, our people, and our product drives creativity and innovation, entrepreneurial leadership and integrity, competitiveness, and collaboration throughout our business and in the market. We depend on our differences to make our team stronger, our workplace more dynamic, and our product accessible to all of our customers.

We’re proud to be an equal‑opportunity employer open to all qualified applicants regardless of race, color, ancestry, religion, sex, national origin, sexual orientation, age, citizenship, marital or familial status, disability, pregnancy, gender identity or expression, veteran status, genetic information, or any other legally protected status. Justworks is fully dedicated to providing necessary support to candidates with disabilities who may require reasonable accommodations. We also provide reasonable accommodations to employees based on their sincerely held religious beliefs, as well as for other covered reasons consistent with applicable federal, state, and local laws. If you're in need of a reasonable accommodation, please reach out to us at View email address on click.appcast.io.

Just Be You

We’re committed to building a culture where everyone feels welcome, supported, and empowered to thrive. We believe that a wide range of perspectives, experiences, and identities strengthens our team and helps us create the kind of workplace—and world— we want to see.