Senior Software Engineer, Core Product Systems

fal is the generative media ecosystem powering the next generation of AI products. We build the infrastructure, tools, and model access that teams need to move from idea to production, and do it at scale without compromise. For developers and enterprises, fal is the foundation that makes generative media not just possible, but practical: a unified platform where high-performance inference, orchestration, and observability come together to unlock new categories of AI-native products. As generative media reshapes industries across a market projected to grow by hundreds of billions over the next decade, fal is becoming the ecosystem that ambitious teams build on. ## About this role This is a **founding role on the small team that owns fal's core product systems** — the connected tissue the whole business runs on: usage, pricing, accounts, access, API keys, and model discovery. You'll join early, own these systems end-to-end (from data model through rollout to operational health), and design the APIs and product surfaces other teams and customers depend on. These are backend systems where **correctness underpins real revenue and customer trust.** You won't inherit five finished systems — you'll prioritize and build. Your **first focus is billing and pricing**: it's our current flagship priority and one of the most-requested things our customers ask for. From there the portfolio grows into accounts, access and identity, API keys, and model discovery. If you like owning the systems that quietly keep a company running — and shipping the product surfaces that make them trustworthy — this is that role. ## What you'll do - **Own billing and pricing first** — metering, usage roll-ups, pricing logic, and the customer/admin surfaces that make cost understandable and trustworthy. - Design **APIs, data models, and product contracts** other teams safely build on. - Grow into the broader portfolio — **accounts, access/identity, API keys, and model discovery** — and the surfaces that expose usage, cost, and access. - Engineer for **correctness and resilience**: source of truth, idempotency, auditability, permissions, observability, graceful failure. - **Own operational health**, including on-call for the systems you build. - Partner across **product, infra, finance, revenue, security, and customer-facing teams** — turning messy, manual workflows into durable systems. ## What we're looking for - 5+ years building reliable, production **backend systems** (Python and/or TypeScript). - Strong **PostgreSQL** — schema design, queries, migrations, performance. - **API & data-model design** for complex product or business domains. - Can ship product and internal surfaces in **React / Next.js / TypeScript**. - Strong **systems judgment** (source of truth, idempotency, auditability, permissions, observability) **and product judgment** (workflows, edge cases, customer trust). - Thrives in **ambiguous, cross-functional work** where product, business logic, and infra overlap; ships a pragmatic v1 that can evolve. Priorities move fast — you're comfortable with that. ## Nice-to-have (the likely differentiators) - **Usage-based billing / metering / pricing** — Stripe, Orb, Metronome, or similar. - **Identity & access** — permissions, SSO, API keys, org/account hierarchy. - **Developer platforms, model registries, or usage/observability dashboards.** - Generative AI / inference APIs or other developer-facing AI products. ## Our stack Python (primary backend) · TypeScript + React/Next.js (product surfaces) · PostgreSQL / SQL · with some migration to Rust underway. ## The team & who you'll work with You'll be an early member of a **small, high-leverage team** (currently ~4) that owns fal's core product and billing systems. You'll work daily with **product and infra engineers**, and partner closely with **finance, revenue, security, and customer-facing teams** — this role lives at the seam of engineering and the business, so cross-functional partnership is core t…