Principal Software Engineer

About the Role: Mend.io is redefining how modern organizations secure software from open source and custom code to AI-generated components. We are looking for a hands-on Principal Software Engineer to join our Mend AI team to build the next generation of application security solutions for AI-powered software. You will take end-to-end ownership of systems, design solid architectures from scratch, and influence both technological decisions and product direction.

What You'll Do

• Design and build solutions from scratch, taking full ownership from idea to production.
• Develop backend systems, leveraging and customizing AI agents, and extend solutions with simple frontend components when needed.
• Act as a technical leader and key decision maker, owning critical architectural and design choices.
• Drive independent research and lead development in new, ambiguous domains, shaping innovative products where standards are still evolving.
• Collaborate closely with security researchers, data scientists, and product managers to turn ideas into production-ready solutions.

What You Bring

• 10+ years of backend software engineering experience with 3+ years in a hands-on technical leadership role (Principal / Tech Lead / Architect).
• Strong experience building systems end-to-end from scratch in a product environment.
• Hands-on experience with a modern programming language (Go preferred; Java or Python is also valuable).
• Experience building or working on systems that integrate AI/LLM-based capabilities into real-world applications.
• Solid understanding of cloud environments and modern development practices (AWS/GCP/Azure).
• Bonus: Familiarity with AI security challenges (e.g., prompt injection, model leakage) and experience with machine learning workflows or tools like LangChain and Hugging Face.

Benefits

• Lead the way in securing AI-powered applications in a rapidly evolving, innovative domain.
• Work in a collaborative, empowering environment built on respect, trust, and growth.
• Full remote flexibility within Poland.