Senior Software Engineer - Tax Calculation

Senior Software Engineer

Rippling's Tax Platform is one of only ~5 companies globally that owns the full tax calculation and filing stack. We process over $30 billion in annual payroll for 1 million+ employees—growing 50% year-over-year. Our systems handle millions of payroll transactions across multiple countries, ensuring tax correctness across 4,000+ jurisdictions while staying compliant with constantly changing tax regulations.

We're looking for a Senior Software Engineer who takes ownership of complex problems, designs robust systems, and delivers high-quality solutions that directly impact millions of tax calculations.

Why This Role

Rare Opportunity

You'd be joining one of only ~5 companies in the world that owns the full tax stack. ADP took 70+ years, Paychex 50+ years, Paycom 25+ years—Rippling built it in 10. Everyone else licenses from vendors. At Rippling, you own the engine.

Uniquely Hard Technical Challenges

• Real-time at scale: Sub-second tax calculations for payroll preview, batch processing of millions of records at month-end, with perfect consistency across retries
• Integration complexity: Filing to thousands of agencies via PDF, XML, fixed-width files, SFTP, web portals, APIs—and yes, some still require paper mail
• Testing without ground truth: No "tax oracle" exists; you'll build validation systems for millions of edge cases across 50 states × 12 months × multiple entity types
• Historical accuracy: Must calculate taxes using rules from any past date as regulations constantly change

The Big Bets You'll Contribute To

• Building an AI-Driven Global Tax Engine with explainable AI for full audit defensibility
• Massive System Scaling to support 100x current volume and enterprise-grade companies
• Expanding International Support to 20+ countries, each with unique tax systems
• Building Distributed Transactional Systems handling $100B+ in tax payments
• Automating Tax Filing to minimize manual intervention at scale

What You'll Build

• FQL (Filing Query Language): Our proprietary DSL encoding tax rules across 4,000+ jurisdictions
• Real-time Tax Calculation: Sub-second calculations at scale with perfect consistency

AI-Powered Compliance Engine: Multi-model validation with human-in-the-loop

What You Will Do

• System Design: Architect scalable, reliable systems that handle billions of dollars in tax calculations with zero tolerance for error
• Ownership & Impact: Own features end-to-end—from design through production—with direct visibility into business outcomes
• Engineering Excellence: Set the bar for code quality, testing practices, and technical documentation within your team
• Reliability & Correctness: Build systems where accuracy is non-negotiable; a single bug can mean compliance failures across thousands of companies
• Global Scale: Solve challenges unique to processing millions of payroll transactions across multiple countries with 4,000+ jurisdictions and evolving regulations
• Collaboration: Partner with compliance, product, and platform teams to translate complex tax requirements into elegant technical solutions

What You Will Have

• 5+ years of software engineering experience
• Strong system design skills with experience building distributed, high-reliability systems
• Proficiency in Python; experience with Django or similar frameworks that follow the MVC pattern (layered architecture).
• Track record of owning and delivering impactful projects autonomously
• Rigorous approach to correctness—you write tests, handle edge cases, and think about failure modes
• Ability to navigate ambiguity and drive clarity in complex problem spaces
• Clear communication and ability to influence technical decisions

Nice to Have

• Experience in fintech, payroll, or tax domains
• Background in compliance-critical systems where correctness is paramount
• Experience with domain-specific languages or rule engines
• Familiarity with MongoDB, Temporal, or event-driven architectures

Tech Stack

• Languages: Python, FQL (proprietary tax DSL), Go
• Framework: Django, MongoEngine
• Database: MongoDB, Redis, PostGre
• Infrastructure: AWS, Kubernetes, Temporal

Observability: Buildkite, Datadog, Sentry