Lead AI Engineer

Sphere, Inc.; San Francisco (CA); On-site; USD 120,000 - 150,000; Full time

Job summary

A tech-driven compliance solutions company in San Francisco is seeking an AI engineer to help build the proprietary Tax Review and Assessment Model (TRAM). This role involves leading feature development, enhancing AI workflows, and working closely with tax experts. Candidates should possess prior experience in AI product development, knowledge of fine-tuning models, and a willingness to tackle tax technical problems. This is a unique opportunity to innovate in the finance AI space with a rapidly growing team.

Qualifications

• Prior experience building AI enabled products, particularly RAG systems.
• Experience fine tuning base models, ideally via RFT.
• Strong understanding of how LLMs and reasoning models function.

Responsibilities

• Lead development of new features for TRAM’s accuracy.
• Work on data and retrieval pipelines for AI workflows.
• Own TRAM’s eval framework and workflows.

Skills

Building AI enabled products

Fine tuning base models

Understanding of LLMs and reasoning models

Tax technical knowledge

Job description

Sphere is using AI to codify the world's international trade law.

We currently help companies like Lovable, Eleven Labs, Replit, Runway AI, Windsurf (+ many more) automate their sales tax, VAT and GST compliance:

• We're growing rapidly (30%+ MoM revenue growth) and helping the fastest growing tech companies around the world including Lovable, Eleven Labs, Replit, Windsurf, Deel, Linktree, Fal, Sierra AI etc

• We’ve spent the last 2 years building local rails into 100+ tax authorities across the world 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 revenue-based compliance)

• We're well funded by a16z, YC, 20vc and Felicis Ventures.

Sphere is looking for an AI engineer to help build out its proprietary Tax Review and Assessment Model (TRAM) across jurisdictions and other compliance areas.

You will be pushing the frontiers of what's possible with AI in the finance space and building the core piece of technology that shape the future of Sphere.

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.

🔮 Multi product play: Indirect tax is just the start; we’re building a compound startup that helps business with all forms of revenue-based compliance.

What you will do:
Within weeks:

• Lead development of new features aimed at increasing TRAM’s test-time accuracy

• Work on the underlying data and retrieval pipelines that help power our AI workflows

• Work directly with our internal tax experts to understand how TRAM can better reason like them
  

Within months:

• Own TRAM’s eval framework and workflows

• Work directly with leading frontier labs to reinforce fine tune models on our proprietary data

Requirements:

• Prior experience building AI enabled products, particularly RAG systems

• Experience fine tuning base models, ideally via RFT

• Willingness to dive into tax technical problems - if you aren’t willing to dive deep on how the model should reason through the tax research process you won’t be effective

• A strong understanding of how LLMs and reasoning models function

Nice to have:

• Experience working with LLMs on legal applications

• Experience with RAG data pipelines and collecting/curating data for the pipeline

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.