Backend Engineer

Employment Type: Full-Time

About Aiwyn

Aiwyn is the fastest-growing software company serving the accounting profession. Founded in 2020, we now work with 150+ of the largest CPA firms in the world. Our mission is to speed up cash flow, save Partner time, and deliver best-in-class client experiences by automating day-to-day firm operations with our Practice Automation solutions. Aiwyn is led by serial entrepreneurs with multiple exits and funded by top-tier investors (Bessemer, KKR, & Revolution). We're passionate about building a remarkable company with world-class people, processes, and technology.

To learn more, visit our website.

About the Role

We’re building the future of tax software by leveraging AI to solve a massive problem: the tax industry is stuck with outdated legacy systems, while tax code complexity and CPA shortages keep increasing. This is a unique opportunity to build a truly innovative product from the ground up. The market is ripe for a better product, and recent AI advances have allowed us to build a better version of what exists. This means we can spend our time making our product as delightful as possible.

As a Backend Engineer at Aiwyn, you will be at the heart of designing and building the robust, scalable, and intelligent systems that power our platform. You'll tackle thorny problems in computational expression generation, data modeling, and the core logic that translates complex tax code into executable software. We're looking for engineers who are product-minded and can think creatively to solve core and immediate problems. You'll have a lot of responsibility and autonomy to make key technical decisions and own projects from architecture to deployment.

Potential Challenges You Might Tackle:

• Designing and implementing a computation engine that auto-updates thousands of interdependent fields based on tax code changes.
• Creating systems that automatically convert IRS documentation into testable, type-safe code and catch errors before they hit production.
• Engineering a semantic graph of tax concepts that powers everything from smart autocomplete to automated test generation.
• Building data pipelines that analyze millions of tax returns to detect patterns, anomalies, and optimization opportunities.
• Scaling our systems to handle complex multi-user interactions and state management across many concurrent sessions.
• Developing and maintaining APIs that are used by our frontend applications and potentially third-party integrators.

Our tech stack includes Next.js, Typescript, Python (FastAPI, SQLAlchemy), Postgres, Google Cloud, and CI/CD.

We’re seeking experienced generalists who are passionate about building robust and scalable backend systems. While we lean towards more senior candidates, we are very open to high-agency, earlier-career individuals who demonstrate a steep growth trajectory and a proactive, problem-solving mindset.

What We're Looking For

• Proven experience in designing, building, and maintaining complex backend systems, ideally with Python and FastAPI.
• Existing comfort deeply integrating AI tools into your workflows (Cursor, Windsurf, etc.).
• Proficiency with databases (PostgreSQL preferred) and data modeling.
• Product sense: an ability to contribute to product ideas, understand product/engineering tradeoffs, and connect backend capabilities to user needs.
• Excellent technical communication skills, especially in a remote, async-first environment. We value clear written and verbal communication.
• A pragmatic approach to engineering; you value shipping and iteration but also care about code quality, testing, and thoughtful system design.
• Comfort with ambiguity and an instinct for surfacing hidden constraints or opportunities, operating effectively with minimal guidance and “seeing around corners.”
• Fluency with AI tools like coding assistants is a baseline requirement; we need engineers who have integrated them into their workflow.