Backend software engineer

We’re looking for an experienced backend engineer to help build and scale the next generation of AI-driven cybersecurity platforms at Theori. You’ll play a key role in architecting and implementing core backend systems that power Xint, our autonomous penetration testing framework. This is a foundational role in our NA engineering team—ideal for someone who thrives on solving complex systems challenges, enjoys designing for scale and reliability, and wants to help define engineering excellence in a fast-growing, AI-first company.

Key Responsibilities

• Architect, develop, and maintain backend services and APIs that power Theori’s AI security platforms.
• Design for performance, scalability, and fault-tolerance across distributed systems.
• Collaborate with product and frontend engineers to define and deliver secure, well-structured APIs.
• Build and optimize data pipelines supporting LLM agent workflows and real-time scanning.
• Establish backend best practices, coding standards, and CI/CD processes for a growing US team.
• Write clean, well-tested, and maintainable code in Python and related technologies.
• Mentor junior engineers and contribute to a strong, collaborative engineering culture.

Requirements

• 5+ years of professional software engineering experience building production systems.
• Strong proficiency in Python, with proven experience developing reliable backend services (FastAPI preferred).
• Solid understanding of system design, distributed architectures, and performance optimization.
• Experience with Redis, PostgreSQL, and Docker-based environments.
• Familiarity with AI/LLM-driven workflows or asynchronous, event-based architectures.
• Comfort working in an early-stage environment with evolving requirements.
• Self-directed, ownership-oriented, and comfortable driving projects from design to deployment.
• Based in US or Canada.

Nice to Have

• Experience with Rust.
• Background in cybersecurity, application security, or vulnerability analysis.
• Knowledge of message queues, task orchestration, or microservices.
• Familiarity with LLM integration, RAG pipelines, or vector databases.
• Prior experience in startups or B2B SaaS environments.
• Previous involvement in building or scaling distributed systems or engineering teams.

What We Offer

Compensation & Benefits

• Competitive salary + equity
• Health, dental, and vision insurance
• Generous PTO policy
• Remote work
• Laptop + home office stipend

Engineering Culture

• Ship features that matter
• Modern Python-based stack (FastAPI, Redis, PostgreSQL, Docker)
• Strong focus on testing and quality
• Clear documentation and processes
• Collaborative, low-ego team

Career growth and mentorship

Work-Life Balance

• Flexible hours, remote-first culture
• Focus on outcomes, not hours