Senior Elixir Engineer

About the Position

Ready to embark on the quest of joining Hack The Box?

Welcome! Super excited you dropped by 🥳

At the end of this journey, you'll become a proud member of Hack The Box, with the ultimate mission to raise cyber resilience, so that every organization can stay ahead of tomorrow’s threats.🚀🔒💻

✨The core mission of the Senior Elixir Engineer:

Join our fast-growing team building the platform that trains the world's cyber workforce. As a Senior Elixir Engineer, you'll own backend and full-stack feature delivery on Phoenix and LiveView - designing resilient OTP systems, clean APIs, and real-time user experiences that scale to millions of users.

Our culture prizes autonomy, technical craft, and the drive to ship secure software that outsmarts attackers.

Responsibilities

• Design and build production Phoenix applications - REST APIs, LiveView UIs, and real-time features on PubSub and Channels.
• Model and evolve data with Ecto and PostgreSQL, writing performant queries and safe, zero-downtime migrations.
• Build fault-tolerant systems with OTP: supervision trees, GenServers, and distributed BEAM patterns where they earn their keep.
• Own background processing and scheduled workloads with Oban, with proper observability via Telemetry and metrics.
• Ship secure-by-default code: authentication/authorization patterns, least-privilege data access, and input hardening - this is a security company.
• Deploy and operate services on Kubernetes/GCP, contributing to CI/CD pipelines and release quality.
• Mentor engineers and contribute to technical leadership through code reviews, design sessions, and coding standards.
• Document decisions and communicate clearly in a remote-first environment, contributing to a culture of thoughtful async collaboration.

Requirements

• 5+ years of professional backend or full-stack development, with 3+ years shipping production Elixir/Phoenix.
• Strong grasp of OTP and the BEAM - processes, supervision, GenServer/GenStage, and when not to reach for them.
• Hands-on experience building interactive UIs with Phoenix LiveView (components, streams, JS hooks).
• Deep Ecto and PostgreSQL knowledge: schema design, query optimization, indexing, migrations.
• Experience with background job systems (Oban preferred) and event-driven architectures.
• Solid testing discipline with ExUnit; comfortable with property-based and integration testing.
• Familiarity with containerized deployment (Docker, Kubernetes) and CI/CD best practices.
• Security-minded engineering: OWASP fundamentals, auth patterns, secure handling of user data.
• Excellent written & verbal communication, especially in remote/async environments, with a bias toward documenting architecture and decisions.

Nice to Have

• Experience with Tailwind CSS, Telemetry, Prometheus, Grafana, and Sentry.

We Offer

• 25 annual leave days
• Paid parental leave
• Home Office Allowance
• Dedicated budget for training and professional development, participation in conferences
• State-of-the-art equipment
• Full access to the Hack The Box lab offerings; so you can learn how to hack 😉
• Flexibility in working hours

About the Company

Hack The Box is the leading cyber readiness platform for the agentic era, battle-testing and upskilling both humans and AI agents to enhance organizational cyber resilience. Trusted by the Fortune 500, government agencies, and MSSPs, the platform delivers threat-informed learning paths consisting of real-world scenarios in gamified labs and live-fire simulations that build and validate offensive and defensive cyber capabilities. With a loyal community of more than 4 million members and 800+ enterprise customers, Hack The Box empowers teams and intelligent systems alike to strengthen cyber defenses and reduce breach risk effectively.

Rapidly growing its international footprint and reach, Hack The Box is headquartered in the UK, with additional offices in the US, Australia, and Greece.

🚨 News & Resources:

• We’re incredibly proud to share that our headquarters in the UK, along with our entities in Greece and the US, have been certified as a Great Place to Work for 4 consecutive years (2023 - 2026).
• In addition, our Greek entity has been recognized among the Best Workplaces in Greece (4th, 2nd, 3rd, 1st) and Europe (7th, 10th, 73rd) during this period - a testament to our strong culture and commitment to creating an exceptional employee experience!

Take a sneak peek at how it is to be part of HTB. Get more insights about our HTB culture and employee experience by visiting the “about us” section of our site, our career site, and Glassdoor.

At Hack The Box, we are committed to fostering a diverse, inclusive, and equitable workplace. We believe that diversity enriches our performance, services, and the communities we serve. As such, we ensure that all job applications are considered solely based on merit, skills, and qualifications. We do not discriminate on grounds of race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status. We are dedicated to providing a fair and respectful work environment that reflects our values.

Hack Your Career, Today. Join us in this epic adventure of cybersecurity at Hack The Box! 🚀🔒💻