Theori Software Engineer - Backend Remote · Full time Company website

Apply for Software Engineer - Backend

Founded in 2016 by Carnegie Mellon University alumni, Theori is a leader in offensive cybersecurity. Our hackers have won DEFCON CTF nine times, and the core engine behind our products was built for DARPA's AI cyber security competition. We're applying that expertise to Xint, an AI-first application security platform spanning Xint Web (autonomous web app penetration testing) and Xint Code (AI-powered code security). Xint has already found hundreds of zero-days in widely used open source projects and is in production with customers like Samsung Electronics, giving security teams hacker-grade testing without hiring an army of pentesters.

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