Full-stack Engineer

Karbon

Location
Australia
Job Type
full-time
Salary
Unknown
Posted
September 17, 2025

Job Description

Karbon is the global leader in practice management software for growth-minded accounting firms. We provide an award-winning, highly collaborative cloud platform that streamlines work and communication, enabling the average accounting firm using Karbon to save 18.5 hours per week, per employee.

We have customers in 34 countries and have grown into a globally distributed team, with our people based throughout the US, Australia, New Zealand, Canada, the United Kingdom, and the Philippines. We are well-funded, ranked #1 on G2, have a fantastic team culture built on our values, are growing rapidly, and making a global impact.

Karbon is seeking a Junior to Mid-Level, Full Stack Software Engineer. This is an exciting time to join the team because we are expanding our organization. In this role, you will be working within an agile development team to design and build interactive web applications. They are responsible for technical specifications and developing and deploying software.

Key Responsibilities :

  • Balance Speed and Quality—You adeptly balance the need for speed with a commitment to quality. You know when to accelerate to meet deadlines and when to focus on detail for perfect outcomes. You have the judgment to navigate these priorities effectively, maintaining a keen eye for both efficiency and excellence.
  • Work effectively as part of a team - Software development is a team sport, where solo victories are rare. It thrives on your robust collaboration and dedication to supporting your colleagues. You will also be working closely with quality assurance team members to resolve issues raised by testing throughout the development cycle.
  • Build and maintain - Your role involves developing innovative products and ensuring the continuous operation of existing ones of the Karbon software applications. You appreciate not only the allure of new technologies but also the importance of iterative improvements on established systems. Your commitment to pioneering and preservation is crucial. You will be responsible for optimizing user experiences, study user-centric data for meaning, experiment with acquisition channels and fine-tune conversion funnels. 
  • Autonomy—You are inherently curious, finding joy in learning and exploration. Faced with challenges and direction rather than predefined solutions, you engage fully and creatively with problems.
  • Own your work—You take genuine pride in your creations, feeling a deep sense of responsibility for the products you develop and their impact on customers. This sense of ownership is paramount, and you share this commitment.
  • Bring your passion and personality—Your creativity, curiosity, and authentic self make the team stronger. If you've worked in highly political environments, you'll find our culture, free from office politics and valuing openness and authenticity, a refreshing change.

Qualifications

  • At least 2 years experience with C#, SQL Server, .Net (MVC, Web API, .Net Core a plus) and JavaScript/TypeScript  
  • Understanding of scalable computing systems, software architecture, data structures, and algorithms
  • Experience in A/B testing and data analysis to optimize key metrics such as user acquisition and retention
  • Excellent analytical skills and problem solving skills 
  • Excellent communication and collaboration skills to work in an international, multi-location team 
  • Has initiative and passion for all things web, and a willingness to go the extra mile 
  • Ability to work as part of a team and able to take pride and ownership in their work
  • Passionate about users behavior, anticipating their needs and preferences 
  • Passionate about developing consumer facing software used globally and across industries
  • A Bachelor’s degree in Computer Science, Mathematics, Statistics, Data Science, or equivalent experience is needed

Why work at Karbon?

  • Gain global experience across the USA, Australia, New Zealand, UK, Canada and the Philippines
  • 4 weeks annual leave plus 5 extra "Karbon Days" off a year
  • Flexible working environment
  • Work with (and learn from) an experienced, high-performing team
  • Be part of a fast-growing company that firmly believes in promoting high performers from within
  • A collaborative, team-oriented culture that embraces diversity, invests in development, and provides consistent feedback
  • Generous parental leave

Karbon embraces diversity and inclusion, aligning with our values as a business. Research has shown that women and underrepresented groups are less likely to apply to jobs unless they meet every single criteria. If you've made it this far in the job description but your past experience doesn't perfectly align, we do encourage you to still apply. You could still be the right person for the role!

We recruit and reward people based on capability and performance. We don’t discriminate based on race, gender, sexual orientation, gender identity or expression, lifestyle, age, educational background, national origin, religion, physical or cognitive ability, and other diversity dimensions that may hinder inclusion in the organization.

Generally, if you are a good person, we want to talk to you. πŸ˜›

If there are any adjustments or accommodations that we can make to assist you during the recruitment process, and your journey at Karbon, contact us at people.support@karbonhq.com for a confidential discussion.

🎯 Who is this job for?

This role is ideal for a Junior to Mid-Level Full Stack Engineer with 2+ years of experience in C#, .NET (MVC/Web API/.NET Core), SQL Server, and JavaScript/TypeScript. Candidates should be comfortable with software architecture, data analysis, and A/B testing, and possess strong team collaboration and problem-solving skills. Passion for user-centric design and continuous product improvement is key.

πŸ’¬ Potential Interview Questions

  1. How would you structure an ASP.NET Core Web API for maintainability?
    Use a layered approach (Controllers → Services → Repositories), register dependencies via built-in DI, validate DTOs with DataAnnotations/FluentValidation, and map models with AutoMapper to keep concerns separated.

  2. Explain how the ASP.NET Core middleware pipeline works and where you’d add auth, logging, and error handling.
    Requests flow through ordered middleware; place exception handling and logging early, authentication/authorization after routing, and static files/compression before MVC to minimize overhead.

  3. What are common async/await pitfalls in .NET and how do you avoid them?
    Avoid blocking calls (.Result/.Wait()), prefer async all the way, use ConfigureAwait(false) in libraries, and guard against fire-and-forget tasks by attaching cancellation and structured logging.

  4. How do you design SQL Server indexes for a frequently filtered, sorted list endpoint?
    Create a composite index matching the WHERE and ORDER BY columns (leftmost selectivity first) and consider INCLUDE columns to make it covering; verify with SET STATISTICS IO and EXPLAIN plans.

  5. When would you use AsNoTracking() in EF Core, and why?
    For read-only queries where change tracking isn’t needed; it reduces memory and speeds up queries, especially on large result sets.

  6. How do you implement safe, versioned API changes without breaking clients?
    Add new versions via URL/headers (ASP.NET API Versioning), keep responses backward compatible, deprecate gradually with headers, and use feature flags to decouple release from deploy.

  7. Describe how you’d design and evaluate an A/B test to improve signup conversion.
    Randomly assign users at the user-id level, predefine primary metrics and guardrails, compute sample size and run time, and use statistical significance (or Bayesian credible intervals) before a rollout.

  8. What metrics and techniques would you use to analyze user retention in a SaaS app?
    Cohort retention curves, activation rate, DAU/WAU/MAU ratios, and funnel step drop-offs; segment by channel/plan and run iterative experiments with event instrumentation and dashboards.

  9. How do you secure a full-stack app end-to-end (web + API)?
    Use HTTPS, cookie-based sessions with SameSite+HttpOnly (or JWT with short TTL + refresh), CSRF protection, input validation, output encoding to prevent XSS, and parameterized queries to prevent SQLi.

  10. What’s your approach to testing and CI/CD for a .NET + TypeScript app?
    Unit test C# with xUnit/NUnit and TS with Jest, add integration tests (WebApplicationFactory/Testcontainers + seeded DB), E2E with Playwright/Cypress, enforce code quality in CI, and deploy via blue-green/rolling with backward-compatible migrations.

πŸ“‹ Job Summary

Karbon, the leading global practice management platform for accounting firms, is hiring a Full-Stack Engineer (Junior to Mid-Level) in Sydney. You'll work with C#, .NET, SQL Server, and TypeScript to build and improve collaborative web apps that save customers hours weekly. Enjoy 4 weeks’ leave plus 5 Karbon Days, flexible work, global team experience, and a culture that values creativity, ownership, and impact. Join a fast-growing, top-rated SaaS company reshaping how professional services teams work.

Required Skills

C# .NET JavaScript

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