Semiotic Labs - Senior Backend Engineer
About The Position
Semiotic Labs is a venture studio building ambitious products at the intersection of AI, security, data, and infrastructure. Our latest ventures include Agentium Studio, a multi-tenant Saas platform for AI-powered financial workflows that operates on confidential documents under SOC 2 controls, accelerating multi-party collaboration for workflows like M&A, diligence, and consulting engagements; AgentVisor, a sandboxing layer for agents with security and observability built in; and Agentium OS, an enterprise platform for agent safety, control, and observability. We’re hiring a Senior Backend Engineer to help build Agentium Studio. You’ll design and ship the backend systems behind core product workflows, APIs, integrations, and parts of the agent runtime layer. This is a high-ownership role for someone who enjoys moving between product engineering and systems design. You should be comfortable turning ambiguous requirements into clear technical plans, shipping production code, and raising the bar for reliability, simplicity, and maintainability. You’ll work closely with engineers, researchers, and product stakeholders on problems at the frontier of AI applications, security, and enterprise software.
Requirements
- 5+ years of professional software engineering experience with substantial backend development experience.
- Strong production experience building backend services in Python.
- Strong experience with asynchronous programming in Python, such as asyncio, async database access, or high-concurrency service development.
- Deep PostgreSQL experience, including schema design, query tuning, transactions, and production migrations.
- Experience designing or implementing multi-tenant data isolation and access control.
- Strong software design fundamentals: modular architecture, testing discipline, maintainability, and clear interface design.
- Experience with Redis or similar infrastructure for caching, queues, rate limiting, or pub/sub.
- Ability to independently own projects and make sound technical tradeoffs in ambiguous environments.
- Strong communication skills and a collaborative, low-ego working style.
Nice To Haves
- Experience with FastAPI, Starlette, Litestar, or another modern Python web framework.
- Experience building backend systems for AI products, agentic workflows, or LLM-powered applications, such as RAG pipelines, tool-calling agents, or orchestration layers.
- Experience with security-sensitive or enterprise systems, including access controls, audit logging, and compliance-driven engineering constraints.
- Experience with OpenTelemetry or comparable production observability tooling.
- Experience with pgvector, SurrealDB, or other vector retrieval systems.
- Exposure to SOC 2, fintech, healthtech, or other regulated environments.
- Experience with agent runtimes, sandboxing, or MCP integrations.
- Familiarity with distributed systems, asynchronous processing, and performance optimization.
- Startup or zero-to-one experience.
- Comfort reading TypeScript or React during frontend-backend integration work.
Responsibilities
- Design, build, and maintain scalable async backend services and APIs in Python.
- Own core systems end-to-end: architecture, implementation, testing, deployment, and operational excellence.
- Build systems for multi-tenant workflows, fine-grained permissions, integrations, and agent-driven product experiences.
- Write and review database migrations and row-level security policies in a compliance-sensitive environment.
- Improve reliability, observability, and performance across critical paths.
- Collaborate closely with product, design, and research to translate user needs into robust backend architecture.
- Contribute to engineering standards, code review culture, and team ways of working.
- Help shape technical direction in a fast-moving environment with evolving product requirements.
Benefits
- Work on technically challenging products at the intersection of AI, security, and enterprise software.
- Join a small, senior team with deep experience in research, distributed systems, and production engineering.
- Have meaningful influence over architecture, product direction, and engineering culture.
- Build products with real-world impact, not just prototypes
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What This Job Offers
Job Type
Full-time
Career Level
Senior
Education Level
No Education Listed
