Backend Software Engineer

Location: San Francisco (Hybrid - in-office 3+ days/week in downtown SF)

About Billables AI

Billables AI is building the AI-powered operating layer for professional service firms, and we're starting where the pain is deepest: the legal industry. Our platform automates the manual overhead that slows lawyers down, bringing together intelligent timekeeping, work activity capture, and operational visibility so firms can understand how work happens and build a more efficient, profitable practice. The best work happens when people aren't buried in administrative burden, and that's exactly the problem we're solving.

Named Legal Tech Company of the Year by Law.com in 2026, Billables AI is one of the fastest-growing companies at the intersection of AI and legal technology. Our team brings together expert AI researchers and veteran startup builders who know how to move fast, build with conviction, and deliver software that sits at the core of how our customers work and generate revenue. Based in San Francisco, we empower everyone on the team to drive meaningful work end-to-end.

About the role

We’re looking for a backend engineer to help build and scale the core systems behind our platform. You’ll work on problems from early ideas through production - shaping requirements, making technical decisions, and working cross-functionally to deliver the right outcomes. You’ll work closely with backend, frontend, and AI engineers, and collaborate with leadership, go-to-market, and customers directly.

You might be a senior engineer who’s worked in startups before, or someone earlier in your career who’s already shown you can get a lot done and take initiative in fast-moving environments. This role is a great fit if you like owning meaningful parts of a system and making pragmatic trade-offs to ship.

What you’ll work on

Design, build, and maintain backend services (Python, gRPC, Postgres, Redis)
Work across a service-oriented architecture and integrate with third-party systems
Own projects end-to-end: clarify requirements, propose solutions, implement, and iterate in production
Scale systems that ingest and process large volumes of activity data
Improve reliability, performance, and observability across services
Make thoughtful trade-offs between speed, quality, and scalability
Contribute to system architecture and long-term technical direction
Step outside your primary lane when needed - frontend, infrastructure, etc

What we’re looking for

Strong track record of deploying and maintaining high-quality, production-ready code in a modern environment
Proficiency in Python and strong backend fundamentals (APIs, data modeling, system design)
Experience building and scaling distributed systems or microservice architectures
A high ownership mindset - you take responsibility for outcomes, not just code
Comfort moving quickly and making decisions without perfect information
Actively use AI tools (LLMs, copilots, etc.) as part of your day-to-day development workflow
Clear communicator who can engage with both technical and non-technical stakeholders
Experience in early-stage or fast-moving environments

Nice to have

Experience with gRPC or similar RPC frameworks
Experience with DevOps/infrastructure (Docker, IaC, CI/CD)
Experience working with AI/ML systems or integrating LLMs into products

Tech stack (not exhaustive)

Python, gRPC, Postgres, Redis, Azure, Docker

Why this role

You’ll work on systems that are central to how our customers run their business
You’ll have real ownership early - not just implementation work
You’ll be part of a small, collaborative team where your decisions meaningfully shape the product and architecture