Principal/Staff Full-Stack GenAI Application Engineer (AI / LegalTech / SF)

Tl;dr — Join Callidus, the most advanced legal generative‑AI platform, as a hands‑on Staff/Principal Full Stack Engineer. Work with state‑of‑the‑art AI, an experienced founder‑led team, and a fresh funding round. Competitive total comp. Hustle culture. San Francisco.

About Callidus

We are entering the golden era of AI. Over the next 5-10 years, breakthroughs will drive a completely new world. Callidus is on a mission to transform the $1T global legal market and we’re well on our way.

Callidus is the most advanced legal generative AI platform on the market today. We offer a uniquely powerful platform, enabling lawyers (as one example) to draft a full 30‑page legal brief in ~10 minutes—saving about a week of effort. We are an engineering‑led organization that empowers talent to build collaboratively toward our mission.

More than 1,000 paying lawyers rely on Callidus today, and ARR is growing >20% MoM, putting us in the top 1% of funded startups at this level. We’re ready to scale and are looking to triple the size of our team.

We work hard, ship fast, and win together. 

Your Role

We want highly talented engineers that want to be hands-on. We don’t want a bunch of managers. You’ll be an individual contributor Software Engineer (everyone at Callidus is a doer). Expect to:

• Design, build, and maintain customer‑facing features end‑to‑end.
• Engineer reliable, scalable Gen‑AI workflows (hybrid RAG, agents, chains of thought, etc.).
• Collaborate daily with lawyers and product to ship measurable user value.
• Own projects like “ingest millions of PDFs and summarize the legally relevant findings for this case”.
• Uphold code quality, security, and performance through reviews and automated tests.

Seniority Level

Hiring for Principal/Staff level Full-Stack engineers. Typically 7-15y post-college experience.

This role will report to the Head of Engineering.

Tech Stack

• Cloud: Azure
• Backend: Python (FastAPI), Redis, Postgres
• Frontend: React / Next.js, Node
• AI: OpenAI, Anthropic, Gemini, Meta, Mistral (choosing best‑in‑class per task)

What We’re Looking For

Core Requirements

• Full-stack engineering in Python + React/Next.
• Proven record of shipping high‑quality products quickly.
• Experience working with LLM APIs and prompt engineering.
• Ability to implement sophisticated LLM techniques (hybrid RAG, hallucination guardrails, agentic workflows, agents, etc.).
• Startup or LLM‑focused‑company experience.
• Ability to commute to San Francisco office ~3-5 days per week.

Soft Skills

• Clear, concise communicator—low words : insights ratio.
• Ownership mindset: you do what you say and surface risks early.
• Ability to work well with ambiguity and low amounts of process.
• Excellent problem solving capabilities.

Passion & Dedication

• Genuine excitement for AI and building category‑defining products.
• Fantastic work ethic & ability to take on a very demanding role (similar culture to xAI, Amazon, Figure, etc.).
• Understanding that this will be much more than a 9‑to‑5. The high effort is easy when you love what you do, the company you’re building, and the mission you’re fulfilling.

Nice‑to‑Haves

• Legal or LegalTech experience.
• Strong DevOps skills on Azure (or AWS/GCP with quick ramp‑up).
• Personal use of AI tooling (Cursor, CoPilot, Midjourney, etc.).
• Automation and productivity‑hack side projects.
• Engineering degree.

Interview Process (fast!)

1. Calibration call with AI Fund sourcing manager, a recruiter, or our Head of Ops for an intake call.
2. Connecting with our Head of Engineering.
3. Meeting another engineer.
4. Final session with CEO.

We move very quickly for the right candidate.

Location

• San Francisco, CA
• No relocation budget, but you are welcome to apply if you are willing to move to San Francisco even if you don't already live here.
• In-office at least 3 days per week.

Compensation

• Base Salary: $215,000 - $255,000
• Meaningful equity
• Comprehensive medical, dental, and vision coverage + Life Insurance
• PTO + company holidays

Why Join Callidus?

• Build on the cutting edge of the most transformative tech since . . . fire?
• Own significant pieces of product in an engineering‑led, high‑talent team.
• Become one of the first 15 employees at a company poised for explosive growth.
• Tackle high‑impact, technically hard problems that competitors avoid.
• Reap outsized rewards in equity and professional growth.

Callidus is an equal opportunity employer and does not discriminate on the basis of race, religion, gender, sexual orientation, gender identity/expression, national origin, disability, age, veteran status, marital status, pregnancy or related condition, or any other basis protected by law.