Senior Full Stack Engineer

Mission: Sphere has built the world’s first AI-native tax engine that helps companies like Eleven Labs, Replit, Runway AI, Windsurf (+ many more) automate their sales tax, VAT and GST obligations: We're growing rapidly (34%+ MoM revenue growth) and helping the fastest growing tech companies around the world including Eleven Labs, Replit, Windsurf, Fathom, Linktree, Photoroom, Sierra AI, Zed etc We’ve spent the last 1.5 years building local rails into tax authorities in both the US and internationally to properly automate compliance processes (no other vendor has done this) We're building the world's first AI-native tax engine (which will be the foundation for a broader cross border compliance platform; think Deel for international billing) We're well funded by Felicis Ventures and YC Sphere is looking for a versatile full stack engineer who can jump on different mission critical areas to help accelerate its production - e.g. filing infrastructure, tax engine and new product areas (input tax, withholding tax, e-invoicing). These areas are key levers towards scaling Sphere and growing ARR, meaning that your work will have a direct impact on the growth of the business Why this is a massive opportunity: 🌍 Massive TAM: Every business around the world needs this. Compliance isn’t optional. 🌬️ Strong macro tailwinds: Businesses are expanding globally at a faster pace, while tax authorities are cracking down on cross-border compliance, driving urgent demand. ✨ AI advantage: Incumbents can’t scale beyond the U.S.; our AI-native tax engine can. 🔮 Product vision: Indirect tax is just the start; we’re building the Deel for international billing. What you will do: Within weeks: Ship features related to a key component of Sphere’s platform - e.g. filing infrastructure Own and manage this key component, driving measurable outcomes Work directly with customers like Eleven Labs, Replit and Windsurf to improve / optimize that key component of the platform (e.g. improve filing generation and submission speed \[x\]%) Within months: Develop expertise across other key components of Sphere’s platform - e.g. tax engine, new products - to manage and execute improvements in this area Lead / mentor additional engineers in component areas that you have worked in What’s important to us: The Dog: Grit > pedigree. Ship fast: If it can be done today, do it today. Self-starter: No hand-holding Accountability: You’ll be held accountable to objective, measurable targets each month. In-person: SF only. Requirements: Strong experience in Python . Our core application backend and data pipeline services are built with Python and Django While frontend / React may not be your primary focus, you’re not afraid to dive in when needed Very strong attention to detail. When you work with numbers this is a non-negotiable - it’s not enough to be 99% right. Nice to have: Experience working with large volumes of transaction data. You’ll be getting very familiar with it! Experience with Django or Python ORM