Senior Software Engineer, Core Product Systems
Founding engineer owning fal's core product systems including billing, pricing, accounts, access, and API keys. Build reliable backend systems (Python/TS) with strong PostgreSQL and React surfaces; first priority is usage-based billing. 5+ years production backend experience required.
About the job
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.
Requirements
- 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
- 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.
Compensation
$190,000 - $230,000 + equity + comprehensive benefits package
Skills
Python, TypeScript, Postgres, React, Next.js, API Design, Data Modeling, Billing Systems, Identity And Access Management
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