Backend Software Engineer
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Theori
US
Summary
Architect and maintain backend services and APIs for AI-driven cybersecurity platforms, specifically the Xint autonomous penetration testing framework. Establish engineering best practices, optimize data pipelines for LLM workflows, and mentor junior engineers.
Job Description
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
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Architect, develop, and maintain backend services and APIs that power Theori’s AI security platforms.
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Design for performance, scalability, and fault-tolerance across distributed systems.
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Collaborate with product and frontend engineers to define and deliver secure, well-structured APIs.
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Build and optimize data pipelines supporting LLM agent workflows and real-time scanning.
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Establish backend best practices, coding standards, and CI/CD processes for a growing US team.
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Write clean, well-tested, and maintainable code in Python and related technologies.
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Mentor junior engineers and contribute to a strong, collaborative engineering culture.
Requirements
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5+ years of professional software engineering experience building production systems.
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Strong proficiency in Python, with proven experience developing reliable backend services (FastAPI preferred).
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Solid understanding of system design, distributed architectures, and performance optimization.
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Experience with Redis, PostgreSQL, and Docker-based environments.
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Familiarity with AI/LLM-driven workflows or asynchronous, event-based architectures.
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Comfort working in an early-stage environment with evolving requirements.
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Self-directed, ownership-oriented, and comfortable driving projects from design to deployment.
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Based in US or Canada.
Nice to Have
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Experience with Rust.
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Background in cybersecurity, application security, or vulnerability analysis.
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Knowledge of message queues, task orchestration, or microservices.
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Familiarity with LLM integration, RAG pipelines, or vector databases.
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Prior experience in startups or B2B SaaS environments.
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Previous involvement in building or scaling distributed systems or engineering teams.
What We Offer
Compensation & Benefits
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Competitive salary + equity
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Health, dental, and vision insurance
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Generous PTO policy
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Remote work
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Laptop + home office stipend
Engineering Culture
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Ship features that matter
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Modern Python-based stack (FastAPI, Redis, PostgreSQL, Docker)
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Strong focus on testing and quality
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Clear documentation and processes
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Collaborative, low-ego team
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Career growth and mentorship
Work-Life Balance
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Flexible hours, remote-first culture
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Focus on outcomes, not hours
Theori is a cybersecurity firm with a mission to make the world more secure by conquering the most difficult cybersecurity challenges.
We empower innovation with security. As a leader in offensive cybersecurity, we always strive to stay one step ahead of attackers. We secure the future by solving the impossible with technology-driven approaches, and serve as a hub that leads positive impact and innovation in the cybersecurity field.
Founded
2016
Company size
51-200 employees
Industry
Computer and Network Security
Org type
Privately Held
Headquarters
Austin, TX
Theori is a cybersecurity firm with a mission to make the world more secure by conquering the most difficult cybersecurity challenges.
We empower innovation with security. As a leader in offensive cybersecurity, we always strive to stay one step ahead of attackers. We secure the future by solving the impossible with technology-driven approaches, and serve as a hub that leads positive impact and innovation in the cybersecurity field.
Founded
2016
Company size
51-200 employees
Industry
Computer and Network Security
Org type
Privately Held
Headquarters
Austin, TX