Principal Software Engineer - Mend AI (AI Security)

Why Mend.io

We are redefining how modern organizations secure software from open source and custom code to AI-generated components. As the creators of the first AI Native AppSec Platform, we help global enterprises stay safe, fast, and compliant in an era of AI-driven development. Our platform combines intelligent automation, deep risk visibility, and developer-first experiences, shaping the future of application security.

We are also committed to building a collaborative, empowering workplace. If you are excited about this role but do not meet every requirement, we encourage you to apply. Your perspective could be exactly what we need!

Mend.io http://Mend.io is building the next generation of application security for AI-powered software, and Mend AI is the team leading that bet. Our product detects and secures AI/ML components inside applications - addressing emerging risks like prompt injection, data leakage, and adversarial attacks - in a domain where the standards are still being written.

We're looking for a Principal Software Engineer to take end-to-end ownership: from research and design through production, on systems that combine classical algorithms with AI/LLM-based capabilities. This is an AI-native role in both senses - you'll build security for AI systems, and you'll work AI-first yourself, using coding agents across the development lifecycle and knowing how to get consistently high-quality results from them.

You'll work as a senior individual contributor with real influence over architecture and product direction, collaborating directly with security researchers, data scientists, and product managers across our Poland and Israel teams (1-hour time difference - genuine daily collaboration, not satellite work).

WHAT YOU'LL DO

- Own solutions end to end - from studying the domain and generating your own ideas, through research and design, to coding, shipping, and supporting them in production.

- Drive independent research in a new domain where problems are not fully defined, balancing innovation with practical, cost-effective engineering

- Build and evolve backend & frontend, extending traditional microservices with AI/LLM-based capabilities

- Use AI agents throughout development - research, design, coding, and testing - to raise both speed and quality

- Work closely with security researchers, data scientists, and product managers to turn ideas into shipped product

WHAT WE'RE LOOKING FOR

- 10+ years of backend software engineering experience, including 3+ years in a hands-on technical leadership role (Principal / Tech Lead / Architect)

- A product mindset: you connect technical decisions to business impact

- A team player with excellent communication skills, who’s not afraid to touch every aspect of modern software product development (e.g. quality, documentation, customer-facing technical discussions)

- Proven experience designing and building systems from scratch in a product environment - including reliable, concurrent, thread-safe services

- Strong hands-on skills in a modern backend language (Go or Python preferred) and the ability to pick up new languages and technologies quickly

- Real, hands-on experience using AI coding agents across the development lifecycle - you know their strengths, their failure modes, and how to guide them to high-quality results

- Solid grounding in cloud environments and modern development practices (AWS, GCP, or Azure)

NICE TO HAVE

- Familiarity with AI security challenges (prompt injection, model leakage, adversarial attacks)

- Experience integrating AI/LLM capabilities into real-world production systems - beyond out-of-the-box API calls (tuning, customization, evaluation)

- Experience with ML workflows (training, deployment, inference) or tools such as LangChain, Hugging Face, or provider SDKs

- Background in application security, cloud security, or DevSecOps

WHY MEND.IO http://Mend.io

Mend.io http://Mend.io is an established leader in application security - an AI-native AppSec platform trusted by enterprises worldwide. Mend AI operates like a startup inside that stability: a small, senior team with a greenfield mandate, direct access to decision-makers, and a product in one of the fastest-moving spaces in security. Our Poland team is a core engineering site, not an outsourcing arm - architecture happens where the engineers are.

Mend.io http://Mend.io is an equal opportunity employer. All aspects of employment are based solely on merit and professional competence, and we're committed to a diverse, inclusive workplace where everyone can do their best work.

Our Culture

At Mend.io https://www.mend.io, we are leading the way in securing AI-powered applications, and we believe the best innovations come from teams where everyone feels valued. We are committed to a workplace built on respect, trust, and growth, where learning and flexibility empower people to do their best work.