Senior Software Engineer

About Mutinex

We're an early-stage B2B SaaS startup with a proven platform, big-name clients, and millions in revenue. We're not chasing unicorn status; we're building a sustainable, long-lasting business (think Bowhead Whale). Mutinex helps marketers understand their ROI and make smarter decisions with their budget.

We're a hybrid team based in Sydney, Melbourne, and New York. We value communication, open-mindedness, and a culture of feedback. All staff receive equity (ESOP), and we offer increasing annual leave based on tenure.

The Role

As a Senior Software Engineer on the GrowthOS team, you'll be a key technical contributor, responsible for building and scaling GrowthOS and MAITE, our core platform that our customers use as their growth co-pilot with Marketing Mix Modelling (MMM) data.

This role is full-stack in nature. You'll have the opportunity to work across our entire technology stack, contributing to our frontend applications to deliver complete, end-to-end features for our users. You'll also build and work with agentic AI platforms and frameworks to build the next generation of the growth co-pilot. You'll apply first-principles software engineering to complex data challenges, taking ownership of a high-impact domain within a fast-growing, product-led startup.

What You'll Do:

• Product Architecture and Development:
  Be a key player in steering the technical design and development of GrowthOS, MAITE. You'll architect and build new features, evolve the platform's architecture for scalability and maintainability, and uphold the highest standards of code quality.
• End-to-End Feature Delivery:
  Take ownership of features that work data from our core data model all the way to the user interface. You'll work on both the backend APIs and the frontend components that consume them, ensuring a seamless user experience.
• Collaboration and Mentorship:
  Work within a cross-functional team of product managers, designers, engineers and data scientists. Share your expertise with team members, championing best practices through code reviews and technical guidance.
• Knowledge Sharing: Share any new techniques, features, frameworks or solutions you've built and delivered with the wider engineering team in our Guilds.

What We're Looking For

• Strong Software Engineering Foundation:
  You have experience building and maintaining production-grade backend systems and services. You live and breathe software engineering principles like SOLID, design patterns, and building testable, maintainable code. Your experience is in software, applied to the data domain.
• Experience Building Data-Intensive Applications:
  You have a proven track record of designing, building, and scaling complex, data-intensive systems in the cloud. You understand the unique challenges of distributed systems, concurrency, and handling large data volumes.
• Full-Stack Capabilities:
  You have experience with modern frameworks (we use React and NestJS). You understand that delivering a great data product means building the user experience that makes it accessible and useful, and you aren't afraid to get your hands dirty in the UI.
• Modern Tech Stack:
  You have hands-on experience with modern cloud infrastructure (we use GCP) and infrastructure-as-code (e.g., Pulumi, Terraform). While experience with data products such as Clickhouse, BigQuery or other OLAP or Analytics Processing platforms is valuable, your core strength should lie with languages such as Typescript, Javascript or any other strongly typed language. We also use Python on the Data platform side.
• A Passion for the Craft:
  You see software engineering as a craft and take pride in your work. This translates into a commitment to building high-quality, reliable, and well-tested software. You don't just write code that works; you write code that is clean, maintainable, and a pleasure for others to work with.
• Growth Mindset:
  You're eager to learn, take on new challenges, and continue to deepen your technical expertise and impact.
• Excellent Communicator:
  You can clearly articulate complex technical ideas to both technical and non-technical stakeholders.
• Proactive Problem-Solver:
  You don't just fix bugs; you identify the root cause and improve the system to prevent future issues.

Why Work With Us?

• Real Customer Impact:
  Your work directly shapes our platform and the success of our customers

• Challenging, Meaningful Work:
  Tackle complex data and infrastructure problems at scale

• Autonomy and Ownership:
  Drive initiatives end-to-end with support when you need it

• Learning and Growth:
  Collaborate with a thoughtful team of engineers and data scientists who love what they do

• Equity Ownership:
  All team members receive equity (ESOP)

• Parental Leave:
  12 weeks paid leave for the primary carer, and 6 weeks for the secondary carer after 2 years

• Generous Time Off:
  20 days of annual leave to start, plus 5 extra days after your first year, and 1 additional day each year after that (up to 30)

• Work from Anywhere:
  Take your laptop and work from anywhere in the world for up to 6 weeks each year

We're Committed to Inclusion

Mutinex is proud to be an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. We welcome applicants of all backgrounds, experiences, identities, and abilities.

If you need adjustments or accommodations during the application process, just let us know, we're happy to support you.

Ready to Join Us?

If this sounds like a place where you'd thrive, we'd love to hear from you. Send us your resume and a short note about why this role excites you—we care more about what drives you than perfect formatting.

Ready to join us?

If you're passionate about building tools that empower teams across the organization and are excited about the potential of AI to transform internal operations, we'd love to hear from you. Send us your resume and a brief cover letter explaining why you're excited about this opportunity.